Coyote Point Systems E350GX, E450GX, E650GX Installation And Administration Manual

Equalizer Installation and Administration Guide

Version 8.6 October 2010

Coyote Point Systems, Inc.

San Jose, California 95112

675 North First Street

Suite 975

The following are Trademarks or Registered Trademarks of Coyote Point Systems Incorporated in the United States and other countries:

Coyote Point™ Equalizer

Equalizer VLB™ Envoy

Equalizer Extreme™ Equalizer Extreme II™ Xcel™ Express™ Emissary™ E250si™ E350si™ E450si™ E550si™ E650si™ E250

GX™

E350

GX™

E450

GX™

E650

GX™

All other brand or product names used in this document are trademarks or registered trademarks of their respective companies or organizations.

THE SPECIFICATIONS AND INFORMATION REGARDING THE PRODUCTS IN THIS MANUAL ARE SUBJECT TO CHANGE WITHOUT NOTICE. ALL STATEMENTS, INFORMATION, AND RECOMMENDATIONS IN THIS MANUAL ARE BELIEVED TO BE ACCURATE BUT ARE PRESENTED WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. USERS MUST TAKE FULL RESPONSIBILITY FOR THEIR APPLICATION OF ANY PRODUCTS.

This document was revised for Equalizer Software Version 8.6.0b.

Contents

Preface 15

In This Guide .................................................................................................................15

Typographical Conventions ...........................................................................................16

Where to Go for More Help ...........................................................................................17

Equalizer Overview 19

Introducing Equalizer .....................................................................................................20

Intelligent Load Balancing ......................................................................................20

Load Balancing Configuration ................................................................................21

Real-Time Server Status Information .....................................................................21

Network Address Translation and Spoofing ...........................................................22

Maintaining Persistent Sessions and Connections ................................................23

Cookie-Based Persistence (Layer 7) ....................................................................................... 23

IP-Address Based Persistence (Layer 4)................................................................................. 24

Is Connection Persistence Always Needed With Session Persistence? ................................. 24

Layer 7 Load Balancing and Server Selection .......................................................24

Geographic Load Balancing ...................................................................................25

Geographic Load Balancing Routing ....................................................................................... 26

Distributing the Geographic Load ............................................................................................ 26

Adding Equalizer to Your Network .................................................................................29

Equalizer E250GX Network Configuration .............................................................29

Using Equalizer E250GX in a Single Network Environment.................................................... 30

Using Equalizer E250GX in a Dual Network Environment ...................................................... 31

Equalizer E350GX, E450GX, E650GX Network Configuration ..............................32

Using Equalizer E350/450/650GX in a Single VLAN Environment.......................................... 33

Using Equalizer E350/450/650GX in a Dual VLAN Environment ............................................ 34

Using Equalizer E350/450/650GX in a Complex VLAN Environment ..................................... 35

Link Aggregation ....................................................................................................36

Using a Second Equalizer as a Backup Unit ..........................................................36

Where Do I Go Next? ....................................................................................................37

Equalizer Installation and Administration Guide 3

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Installing and Configuring Equalizer Hardware 39

Before You Turn Equalizer On for the First Time ..........................................................40

Stepping Through the Hardware Installation .................................................................40

Setting Up a Terminal or Terminal Emulator .................................................................41

Serial Connection ...................................................................................................41

Performing Basic Equalizer Configuration .....................................................................41

Starting to Configure Equalizer ..............................................................................42

Configuring External and Internal Interfaces on E250GX ......................................42

Configuring the Default VLAN on E350/450/650GX ...............................................43

Setting the Time Zone ............................................................................................44

Setting the Date and Time ......................................................................................44

Adding Administrative Interface Logins ..................................................................44

Changing Equalizer’s Console Password ..............................................................45

Upgrading Equalizer Software ................................................................................45

Shutting Down Equalizer ........................................................................................46

Adding Alternate DNS Servers ...............................................................................46

Managing Remote Access to the Equalizer ...................................................................47

Managing the Remote Access Account .................................................................47

Using the Remote Access Account ........................................................................47

Configuring a Second Equalizer As a Backup (Failover) ...............................................48

Configuring DNS and Firewalls for Envoy .....................................................................48

Configuring the Authoritative Name Server to Query Envoy ..................................48

Using Geographic Load Balancing with Firewalls ..................................................48

Testing Basic Connectivity ............................................................................................49

Using the Administration Interface 51

Logging In and Navigating the Administrative Interface ................................................52

Logging In ...............................................................................................................52

Navigating Through the Interface ...........................................................................53

Managing Access to Equalizer ......................................................................................55

Viewing and Changing GUI and SSH Access ........................................................55

Updating the Administration Interface Certificate ..........................................................56

Managing Multiple Interface Users ................................................................................56

Objects and Permissions ........................................................................................57

Viewing or Modifying Login Permissions ................................................................59

Adding a Login .......................................................................................................60

Deleting a Login .....................................................................................................61

Entering Names for Equalizer Objects ..........................................................................61

4 Equalizer Installation and Administration Guide

Equalizer Network Configuration 63

VLAN Basics ..................................................................................................................64

Configuring VLANs on Equalizer ................................................................................... 65

Configuring VLANs Using the VLAN Wizard ..........................................................66

Adding a VLAN Using the Add VLAN Command ...................................................67

Modifying a VLAN ...................................................................................................68

Deleting a VLAN .....................................................................................................70

Managing Gigabit Switch Ports .....................................................................................71

Switch Administration Interface .............................................................................. 72

Viewing Link Status ................................................................................................................. 72

Viewing Current Port Settings.................................................................................................. 72

Editing Port Settings ................................................................................................................ 73

Commiting and Applying Switch Port Configuration Changes ................................................. 74

Switch Interface Usage Scenarios .........................................................................75

Resetting the Front-Panel Switch ...........................................................................75

Switch Interface Notes for Pre-GX Equalizer Hardware .........................................75

Configuring Static Routes .............................................................................................. 76

Adding a Static Route .............................................................................................76

Modifying a Static Route ........................................................................................77

Deleting a Static Route ...........................................................................................77

Configuring Servers on Your Network ...........................................................................78

Configuring Routing on Servers .............................................................................78

Server Configuration Constraints ...........................................................................78

Configuring Equalizer Operation 81

Licensing Equalizer .......................................................................................................82

Requesting a License Online ................................................................................. 82

Requesting a License Offline .................................................................................84

Modifying Global Parameters ........................................................................................85

Global Probe Parameters .......................................................................................85

Global Networking Parameters ..............................................................................87

Setting Up a Failover Configuration ...............................................................................90

Failover Partition .................................................................................................... 90

Failover Between Different Hardware & Software Versions ...................................91

Using Version 8.6 with Version 8.5.1 and GX/‘si’ Hardware.................................................... 91

Using a GX and an ‘si’ in Failover with Version 8.6 ................................................................. 92

Setting Up or Modifying Failover Using the Failover Wizard ..................................92

Enabling Failover Using the Failover Tabs .............................................................94

Manually Enabling Failover...................................................................................................... 94

Modifying the Failover Configuration ......................................................................99

Equalizer Installation and Administration Guide 5

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Disabling the Failover Configuration ......................................................................99

Re-enabling Failover After Disabling ....................................................................100

Clearing the Failover Configuration ......................................................................101

Modifying VLANs with Failover Configured ..........................................................101

Changing from a Multi-VLAN to a Single-VLAN Network Configuration ................................ 101

Managing System Time and NTP ................................................................................103

NTP and Plotting ..................................................................................................103

Selecting an NTP Server ......................................................................................104

General System Maintenance .....................................................................................106

Saving or Restoring Your Configuration ...............................................................106

Using a Backup Archive Created on Another Equalizer......................................................... 106

Backing Up Your Configuration.............................................................................................. 106

Restoring a Saved Configuration ........................................................................................... 107

Shutting Down Equalizer ......................................................................................107

Rebooting Equalizer .............................................................................................107

Creating a System Information Archive ................................................................108

Upgrading Equalizer Software ..............................................................................108

Administering Virtual Clusters 111

Working with Virtual Clusters .......................................................................................112

Adding a Layer 7 Virtual Cluster ...........................................................................113

Modifying a Layer 7 Virtual Cluster ......................................................................114

Layer 7 Required Tab ............................................................................................................ 114

Layer 7 Probes Tab................................................................................................................ 115

Layer 7 Persistence Tab ........................................................................................................ 116

LB Policy Tab ......................................................................................................................... 117

Layer 7 Networking Tab ......................................................................................................... 118

Layer 7 Security > Certificates Tab (HTTPS only) ................................................................. 119

Layer 7 Security > SSL Tab (HTTPS only) ............................................................................ 120

Adding a Layer 4 Virtual Cluster ...........................................................................121

Modifying a Layer 4 Virtual Cluster ......................................................................122

Layer 4 Required Tab ............................................................................................................ 122

Layer 4 Probes Tab................................................................................................................ 124

Layer 4 Persistence Tab ........................................................................................................ 125

LB Policy Tab ......................................................................................................................... 125

Deleting a Virtual Cluster ......................................................................................126

Copying an Existing Virtual Cluster ......................................................................126

Configuring a Cluster’s Load-Balancing Options .........................................................127

Equalizer’s Load Balancing Policies .....................................................................127

Equalizer’s Load Balancing Response Settings..................................................................... 128

Aggressive Load Balancing.................................................................................................... 128

Dynamic Weight Oscillations.................................................................................................. 128

6 Equalizer Installation and Administration Guide

Configuring a Cluster to Use Server Agents ........................................................128

Enabling Persistent Server Connections ..............................................................129

Enabling Sticky Connections ................................................................................................. 129

Enabling Cookies for Persistent Connections........................................................................ 130

Enabling the Once Only and Persist Options ....................................................... 131

Enabling Both the Once Only and Always Options................................................................ 133

Enabling Once Only and No Header Rewrite for HTTPS .....................................133

Enabling Once Only and Compression ................................................................134

Using Active Content Verification (ACV) ..............................................................134

Using ACV ............................................................................................................................. 134

Enabling ACV ........................................................................................................................ 135

HTTPS Header Insertion ......................................................................................136

Specifying a Custom Header for HTTPS Clusters ............................................... 136

Performance Considerations for HTTPS Clusters ................................................137

HTTPS Performance and Xcel SSL Acceleration .................................................................. 137

Providing FTP Services on a Virtual Cluster ........................................................138

FTP Cluster Configuration ..................................................................................................... 138

Managing Servers ....................................................................................................... 140

The Server Table ..................................................................................................140

Server Software Configuration .............................................................................141

Adding a Server to a Cluster ................................................................................142

Modifying a Server ...............................................................................................144

Configuring Outbound NAT .................................................................................. 145

Enabling Outbound NAT........................................................................................................ 146

Configuring Outbound NAT for a Server................................................................................ 146

Using Outbound NAT on a Server IP in Multiple Clusters ..................................................... 147

Adjusting a Server’s Initial Weight ........................................................................147

Setting initial Weights for Homogenous Clusters................................................................... 147

Setting initial Weights for Mixed Clusters .............................................................................. 148

Setting Maximum Connections per Server ...........................................................148

Maximum Connections Limits, Responders, and Hot Spares ............................................... 149

Interaction of Server Options and Connection Processing ...................................149

Shutting Down a Server Gracefully ......................................................................149

Removing a Layer 7 Server from Service.............................................................................. 150

Removing a Layer 4 Server from Service.............................................................................. 150

Deleting a Server ..................................................................................................150

Automatic Cluster Responders ....................................................................................152

Managing Responders .........................................................................................152

Adding a Responder .............................................................................................152

Modifying a Responder ........................................................................................154

Plotting Responder Statistics ...............................................................................154

Using Regular Expressions in Redirect Responders ...........................................154

Equalizer Installation and Administration Guide 7

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Example 1 -- HTTPS Redirect................................................................................................ 155

Example 2 -- Multi-Hostname Redirect .................................................................................. 156

Example 3 -- Directory Redirect ............................................................................................. 157

Using Responders in Match Rules .......................................................................158

Creating a Match Rule for a “Sorry Page”.............................................................................. 158

Creating a Match Rule to Redirect All Traffic for a Specific URL ........................................... 159

More Responder Examples ..................................................................................160

Responders and Hot Spares ................................................................................160

Configuring Smart Events ............................................................................................161

Smart Events Components ..................................................................................161

Smart Event Trigger Expressions .........................................................................161

Smart Event Action Functions and Variables .......................................................163

Smart Event Operators .........................................................................................165

Smart Event Configuration Parameters ................................................................165

Using IPMI to Power Servers On/Off ....................................................................166

Complex Smart Event Expressions ......................................................................166

Managing Smart Events .......................................................................................167

Adding a Smart Event ............................................................................................................ 167

Editing a Smart Event ............................................................................................................ 168

Deleting a Smart Event .......................................................................................................... 168

Displaying Smart Event Statistics .......................................................................................... 168

Using the Smart Event Expression Editor ............................................................168

Smart Event Examples .........................................................................................169

Logging a Message When Server Count is Low .................................................................... 169

Unquiescing a Server When Server Count is Low ................................................................. 170

Using IPMI to Conserve Server Resources ........................................................................... 172

Configuring Direct Server Return (DSR) .....................................................................177

Configuring Servers for Direct Server Return .......................................................179

Configuring Windows Server 2003 and IIS for DSR .............................................................. 180

Configuring a Linux System running Apache for DSR ........................................................... 180

Configuring a Loopback Interface on Other Systems for DSR............................................... 181

Weak and Strong Host Models and DSR............................................................................... 181

Testing Virtual Cluster Configuration ...........................................................................182

Testing Your Basic Configuration ................................................................................182

Monitoring Equalizer Operation 183

Displaying Equalizer System Information ....................................................................184

Displaying General Cluster Status ...............................................................................185

Displaying the System Event Log ................................................................................186

Displaying the Virtual Cluster Summary ......................................................................187

Displaying Global Connection Statistics ......................................................................189

8 Equalizer Installation and Administration Guide

Displaying Cluster Statistics ........................................................................................191

Displaying Server Statistics .........................................................................................191

Displaying Envoy Statistics ..........................................................................................191

Displaying Site Statistics .............................................................................................192

Plotting Global Performance History ...........................................................................193

Plotting Cluster Performance History ..........................................................................193

Plotting Server Performance History ...........................................................................194

Plotting Match Rule Performance History ....................................................................196

Plotting Responder Performance History ....................................................................196

Plotting GeoCluster Performance History ....................................................................196

Plotting Site Performance History ................................................................................197

Exporting Usage Statistics ...........................................................................................198

Configuring Custom Event Handling ...........................................................................200

Forwarding Equalizer Log Information .................................................................200

Specifying a Command to Run on an Event ........................................................200

Configuring Email Notification ..............................................................................201

Disabling Email Notification ..................................................................................202

Browsing Equalizer Configurations using SNMP .........................................................203

Enabling the SNMP Agent ....................................................................................204

Setting Up an SNMP Management Station .......................................................... 205

MIB Description ....................................................................................................205

Siblings .................................................................................................................................. 206

Configuration and Status ....................................................................................................... 206

Clusters.................................................................................................................................. 206

Servers .................................................................................................................................. 206

Events.................................................................................................................................... 206

Using Match Rules 207

Why Match Rules? ......................................................................................................208

Match Rules Overview ......................................................................................... 208

Match Rule Processing ........................................................................................209

Match Rules, the Once Only Flag, and Cookies ..................................................210

General Match Expressions and Match Bodies ...........................................................211

Match Expressions ...............................................................................................211

Match Bodies ........................................................................................................212

Match Rule Definitions .........................................................................................213

Managing Match Rules ................................................................................................214

The Match Rules Table ........................................................................................214

Equalizer Installation and Administration Guide 9

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The Default Match Rule ........................................................................................215

Creating a New Match Rule .................................................................................216

Modifying a Match Rule ........................................................................................219

Removing a Match Rule ....................................................................................... 219

Match Functions ..........................................................................................................219

Match Function Notes ..........................................................................................224

Match Rule Behavior When Server Status is not ‘Up’............................................................ 224

Considering Case in String Comparisons .............................................................................. 224

Regular Expressions .............................................................................................................. 225

Supported Headers ................................................................................................................ 225

HTTPS Protocol Matching...................................................................................................... 225

Supported Characters in URIs ............................................................................................... 226

Logical Operators and Constructs in the GUI .......................................................226

Using Responders in Match Rules ..............................................................................227

Example Match Rules ..................................................................................................227

Parsing the URI Using Match Rules .....................................................................227

Changing Persistence Settings Using Match Rules .............................................229

Changing the Spoof (SNAT) Setting Using Match Rules .....................................231

Server Selection Based on Content Type Using Match Rules .............................233

Using the Custom Load Balancing Policy with Match Rules ................................235

Administering GeoClusters 237

Overview of Geographic Load Balancing with Envoy ..................................................238

Overview of Configuration Process ......................................................................238

Overview of Envoy Site Selection ........................................................................238

Licensing and Configuring Envoy ................................................................................242

Enabling Envoy ....................................................................................................242

Configuring the Authoritative Name Server to Query Envoy ................................242

Using Envoy with Firewalled Networks ................................................................244

Using Envoy with NAT Devices ............................................................................244

Upgrading a Version 7 GeoCluster to Version 8 ..................................................244

Working with GeoClusters ...........................................................................................245

Adding a GeoCluster ............................................................................................ 245

Viewing and Modifying GeoCluster Parameters ...................................................246

Deleting a GeoCluster ..........................................................................................248

Displaying Envoy Statistics ..................................................................................249

Plotting GeoCluster History ..................................................................................249

Working with Sites .......................................................................................................249

Adding a Site to a GeoCluster ..............................................................................249

Displaying and Modifying Site Information ...........................................................251

10 Equalizer Installation and Administration Guide

Deleting a Site from a GeoCluster ........................................................................253

Displaying Site Statistics ......................................................................................253

Plotting Site History ..............................................................................................253

Envoy Configuration Worksheet .................................................................................. 254

Server Agent Probes 255

Enabling Agents ...................................................................................................255

Server Agents and Load Balancing Policies ........................................................256

Server Agents and Server ‘Down’ Conditions ......................................................256

Sample Server Agent in Perl ................................................................................ 256

Timeout Configuration 259

Connection Timeouts ...................................................................................................260

HTTP and HTTPS Connection Timeouts .............................................................260

The Once Only Option and HTTP / HTTPS Timeouts ........................................................... 263

Layer 4 Connection Timeouts ..............................................................................263

Application Server Timeouts ................................................................................264

Connection Timeout Kernel Variables ..................................................................264

Server Health Check Probes and Timeouts ................................................................265

ICMP Probes ........................................................................................................265

High Level TCP and ACV Probes ........................................................................265

TCP Probe Aggregation......................................................................................................... 268

Server Agent Probes ............................................................................................269

Agent Probe Process............................................................................................................. 269

Enabling and Disabling Server Agents .................................................................................. 269

Using Reserved IP Addresses 271

Outbound NAT and Failover .................................................................................272

Regular Expression Format 273

Regular Expressions in Match Rules and Responders ...............................................273

Terms ...................................................................................................................273

Learning About Atoms ..........................................................................................273

Creating a Bracket Expression .............................................................................274

Escape Sequences ..............................................................................................275

Matching Expressions ..........................................................................................275

Using Certificates in HTTPS Clusters 277

Using Certificates in HTTPS Clusters ..........................................................................278

About Server Certificates ..................................................................................... 278

About Client Certificates .......................................................................................279

General Certificate Guidelines .............................................................................279

Equalizer Installation and Administration Guide 11

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Software vs. Hardware Encryption/Decryption .....................................................280

Using Certificates in a Failover Configuration ......................................................280

Enabling HTTPS with a Server Certificate ...................................................................280

Enabling HTTPS with Server and Client Certificates ...................................................281

Generating a CSR and Getting It Signed by a CA .......................................................282

Generating a CSR using OpenSSL ......................................................................282

Generating a Self-Signed Certificate ...........................................................................283

Preparing a Signed CA Certificate for Installation .......................................................283

Installing Certificates for an HTTPS Cluster ................................................................284

Using IIS with Equalizer ...............................................................................................286

Generating a CSR and Installing a Certificate on Windows Using IIS .................286

Converting a Certificate from PEM to PKCS12 Format ...............................................287

Private Key Storage for Cluster Certificates ................................................................288

Clearing Secure Key Storage on Xcel I ................................................................289

Configuring Cipher Suites ............................................................................................289

Default Cipher Suites ...........................................................................................289

Updating the Cipher Suites Field ..........................................................................289

No Xcel (Software) and Xcel II Cipher Suites .......................................................290

Xcel I Cipher Suites ..............................................................................................290

Equalizer VLB 293

Equalizer VLB Basic ....................................................................................................294

Using VLB Basic ...................................................................................................294

Equalizer VLB Advanced .............................................................................................295

Using VLB Advanced ...........................................................................................295

Installation and Licensing ............................................................................................296

Enabling Equalizer VLB ...............................................................................................296

Enabling VLB Agents on a Cluster ..............................................................................297

Disabling VLB Agents for a Cluster .............................................................................298

Disabling Equalizer VLB for all Clusters ......................................................................298

Associating a Server with a Virtual Machine ...............................................................299

Smart Control Event Examples Using VLB .................................................................299

Configuring Multiple Hot Spares (VLB Only) ........................................................300

Rebooting an Unresponsive Virtual Machine (VLB only) .....................................302

VLB Logging ................................................................................................................304

VLB Plotting .................................................................................................................305

12 Equalizer Installation and Administration Guide

Additional Operational Notes .......................................................................................305

Troubleshooting 307

Equalizer Doesn’t Boot for First Time ..........................................................................307

Terminal or terminal emulator not connected to Equalizer .................................................... 307

Clients Time Out Trying to Contact a Virtual Cluster ...................................................308

Equalizer is not gatewaying reply packets from the server.................................................... 308

Test client is on the same network as the servers ................................................................. 308

No active servers in the virtual cluster ................................................................................... 308

Equalizer is not active............................................................................................................ 308

Primary and Backup Equalizer Are in a Conflict Over Primary .............................................. 308

Backup Equalizer Continues to Boot ...........................................................................308

Primary and Backup Equalizer Are in a Conflict over Primary............................................... 308

Can’t View Equalizer Administration Pages ................................................................308

Equalizer is not active............................................................................................................ 308

Equalizer Administration Interface Unresponsive ........................................................309

Equalizer Administration Page Takes a Long Time to Display ....................................309

DNS server configured on Equalizer is not responding ......................................................... 309

Equalizer Doesn’t Respond to Pings to the Admin Address ........................................309

Equalizer is not powered on .................................................................................................. 309

Equalizer isn't connected to your network ............................................................................. 309

Administration address not configured on the external interface ........................................... 309

Browser Hangs When Trying to Connect Via FTP to an FTP Cluster .........................309

FTP server returns its private IP address in response to a “PASV” command ...................... 309

Return Packets from the Server Aren’t Routing Correctly ...........................................310

IP spoofing is enabled ........................................................................................................... 310

Web Server Cannot Tell Whether Incoming Requests Originate Externally or Internally ..

310

IP Spoofing is not enabled..................................................................................................... 310

Why aren't my clusters working if the server status is "up"? ....................................... 310

Context Help Does Not Appear ...................................................................................310

Restoring IP Access to the Administrative Interface ....................................................310

Restoring Login Access to the Administrative Interface ..............................................311

Log Contains ‘interrupted system call’ Messages .......................................................311

Log Contains SSL Errors with “wrong version number” ..............................................312

GUI Always Reports All Configuration Errors ..............................................................312

Updating the Configuration File Sequence Number ....................................................312

License and Warranty 315

Equalizer Installation and Administration Guide 13

Table of Contents

Additional Requirements and Specifications 317

Short-Circuit Protection ............................................................................................... 317

Power Supply Cord ......................................................................................................317

Installation into an Equipment Rack ............................................................................317

Chassis Warning—Rack-Mounting and Servicing .......................................................318

Battery .........................................................................................................................318

Specifications ..............................................................................................................318

Power Requirements ............................................................................................318

Power Consumption ............................................................................................. 319

110V Test Results.................................................................................................................. 319

220V Test Results.................................................................................................................. 320

Operating Environment ........................................................................................320

Physical Dimensions ............................................................................................320

Regulatory Certification ........................................................................................320

Glossary 321

Index 331

14 Equalizer Installation and Administration Guide

Preface

This version of the Equalizer Installation and Administration Guide tells you how to install, configure, and maintain Equalizer™ load balancers running Release 8.6 of the Equalizer software.

In This Guide

This guide contains the following chapters and appendices:

• Chapter 1, “Equalizer Overview”, contains detailed descriptions of Equalizer concepts and terminology. This chapter includes information to help you plan your Equalizer configuration. If you are setting up Equalizer for the first time, be sure to read the Overview chapter before attempting to install and configure your system.

• Chapter 2, “Installing and Configuring Equalizer Hardware”, provides comprehensive instructions for installing Equalizer hardware and setting up Equalizer to work with your networks and servers.

• Chapter 3, “Using the Administration Interface”, discusses how to use Equalizer’s HTML-based administration interface, including adding administrative logins with distinct permissions.

• Chapter 4, “Equalizer Network Configuration”, covers VLAN and switch port configuration, as well as how to define static routes on Equalizer.

• Chapter 5, “Configuring Equalizer Operation”, tells you how to configure system and global resources through the Equalizer Administration Interface, including setting up a failover configuration.

• Chapter 6, “Administering Virtual Clusters”, tells you how to add and remove virtual clusters and servers, changing load balancing options, and shutting down servers.

• Chapter 7, “Monitoring Equalizer Operation”, describes how to view information, statistics, and graphical displays about Equalizer’s operation.

• Chapter 8, “Using Match Rules”, shows you to create match rules that distribute requests based on a request’s attributes.

• Chapter 9, “Administering GeoClusters”, shows you how to use the optional Envoy product to add and remove geographic clusters and sites and change geographic load balancing and targeting options.

• Appendix A, Server Agent Probes, describes how to develop custom server agents.

• Appendix B, Timeout Configuration, provides detailed desccriptions of all the timeout parameters used by Equalizer and the effect that each has on client/server connections and server probes.

• Appendix C, Using Reserved IP Addresses, describes how to configure Equalizer to distribute requests to servers assigned IP addresses on reserved, non-routable networks.

• Appendix D, Regular Expression Format, discusses Equalizer’s regular expressions, components, formats, and usage.

• Appendix E, Using Certificates in HTTPS Clusters, shows you how to obtain and install certificates for HTTPS clusters.

Equalizer Installation and Administration Guide 15

Chapter : Preface

• Appendix F, Equalizer VLB, describes the optional Equalizer VLB product, which supports integration of Equalizer with VMware Infrastucture and ESX Server virtual machine configurations.

• Appendix G, Troubleshooting, helps you to diagnose problems with Equalizer.

• Appendix H, License and Warranty, contains the complete License and Warranty information.

• Appendix I, Additional Requirements and Specifications, lists additional hardware related requirements for Equalizer installations.

• The Glossary defines the technology-specific terms used throughout this book.

•Use the Index to help find specific information in this guide.

Typographical Conventions

The following typographical conventions appear throughout this guide:

Italics indicates the introduction of new terms, is used to emphasize text, and indicates variables and file names.

Boldface text highlights command names in instructions and text entered by the user.

Boldface text highlights

graphical administrative interface screen elements: labels, buttons, tabs, icons, etc.

Courier text is used to denote computer output: messages, commands, file names, directory names, keywords, and

syntax exactly as displayed by the system.

Sequences such as “

Equalizer > Status > Event Log” are used to indicate the Administrative Interface click-path

the user should follow to display the information or form relevant to the task at hand. In this example, the user would click on the Equalizer system name displayed on the left side of the Administrative Interface, then click on the

Status tab on the right side of the screen, and then click on the Event Log sub-tab. Similarly, “Cluster > Probes”

starts by selecting a cluster name in the left frame tree, and “Server > Reporting” starts with a server name.

1. Numbered lists show steps that you must complete in the numbered order.

• Bulleted lists identify items that you can address in any order.

Note – Highlights important information and special considerations.

Caution – Warns when an action could result in loss of data or damage to your equipment.

Emphasizes safety information or information critical to Equalizer operation.

16 Equalizer Installation and Administration Guide

Chapter : Preface

Where to Go for More Help

This Equalizer Installation and Administration Guide is part of the product documentation delivered with Equalizer’s browser-based Administrative Interface. You can display the appropriate manual section for any interface screen by selecting contains links to the Release Notes for the currently running software version, and other documentation.

Hardcopy documentation provided with every Equalizer includes the Getting Started Guide and the basic Configuration Guide. These two documents are designed to help you get Equalizer out of the box and working with your first virtual clusters. The Basic Configuration Guide also contains a documentation, including support documents that help you configure Equalizer for a variety of environments. The latest Resource CD content is available on the web at:

http://docs.coyotepoint.com

Customer Support contact information is available from http://www.coyotepoint.com/support.php. Register today to get access to the provides you with a login so you can access these benefits:

•

Support FAQs: answers to our customer's most common questions.

•

Moderated Customer Support Forum: ask questions and get answers from our support staff and other

Equalizer users.

Help > Context help from the menu at the top of the interface. The Help menu also

Resource CD with copies of all product

Coyote Point Support Portal (http://support.coyotepoint.com). Registration

•

Software upgrades and security patches: access to the latest software updates to keep your Equalizer

current and secure.

•

Online device manuals, supplements, and release notes: the latest Equalizer documentation and

updates.

•

Links to additional resources, and more.

17 Equalizer Installation and Administration Guide

Chapter : Preface

18 Equalizer Installation and Administration Guide

Chapter 1:

Equalizer Overview

Introducing Equalizer ..............................................................................................................................20

Intelligent Load Balancing .................................................................................................................20

Load Balancing Configuration ...........................................................................................................21

Real-Time Server Status Information ................................................................................................21

Network Address Translation and Spoofing ......................................................................................22

Maintaining Persistent Sessions and Connections ...........................................................................23

Cookie-Based Persistence (Layer 7)......................................................................................... 23

IP-Address Based Persistence (Layer 4) .................................................................................. 24

Is Connection Persistence Always Needed With Session Persistence? ................................... 24

Layer 7 Load Balancing and Server Selection ..................................................................................24

Geographic Load Balancing ..............................................................................................................25

Geographic Load Balancing Routing......................................................................................... 26

Distributing the Geographic Load.............................................................................................. 26

Adding Equalizer to Your Network ........................................................................................................29

Equalizer E250GX Network Configuration ........................................................................................29

Using Equalizer E250GX in a Single Network Environment...................................................... 30

Using Equalizer E250GX in a Dual Network Environment ........................................................ 31

Equalizer E350GX, E450GX, E650GX Network Configuration .........................................................32

Using Equalizer E350/450/650GX in a Single VLAN Environment ........................................... 33

Using Equalizer E350/450/650GX in a Dual VLAN Environment .............................................. 34

Using Equalizer E350/450/650GX in a Complex VLAN Environment ....................................... 35

Link Aggregation ...............................................................................................................................36

Using a Second Equalizer as a Backup Unit .....................................................................................36

Where Do I Go Next? ...............................................................................................................................37

Equalizer Installation and Administration Guide 19

Chapter 1: Equalizer Overview

Introducing Equalizer

Equalizer® is a high-performance content switch that features:

• Intelligent load balancing based on multiple, user-configurable criteria

• Non-stop availability with no single point of failure, through the use of redundant servers in a cluster and the optional addition of a failover (or backup) Equalizer

• Layer 7 content-sensitive routing

• Connection persistence using cookies or IP addresses

• Real-time server and cluster performance monitoring

• Server and cluster administration from a single interface

• SSL acceleration (on Equalizer models with Xcel SSL Hardware Acceleration)

• Data compression (on Equalizer models with Express Hardware GZIP Compression)

• Geographic load balancing (with the optional Envoy software add-on)

This chapter is an introduction to Equalizer’s basic load balancing and application acceleration capabilities, for those who have some networking experience but may not have previously used an appliance like Equalizer.

Intelligent Load Balancing

Equalizer functions as a gateway to one or more sets of servers organized into virtual clusters. When a client submits a request to a site that Equalizer manages, Equalizer identifies the virtual cluster for which the request is intended, determines the server in the cluster that will be best able to handle the request, and forwards the request to that server for processing.

To route the request, Equalizer modifies the header of the request packet with the appropriate server information and forwards the modified packet to the selected server. Depending on the cluster options chosen, Equalizer may also modify the headers in server responses on the way back to the client.

Equalizer support clusters that route requests based on either Layer 4 (TCP or UDP) or Layer 7 (HTTP or HTTPS) protocols. Layer 4 is also referred to as the Transport Layer, while Layer 7 is referred to as the Application Layer. These terms come from the OSI and TCP/IP Reference Models, abstract models for network protocol design.

In general, Layer 4 clusters are intended for configurations where routing by the destination IP address of the request is sufficient and no examination of the request headers is required. Layer 7 clusters are intended for configurations where routing decisions need to be made based on the content of the request headers. Equalizer evaluates and can modify the content of request headers as it routes packets to servers; in some cases, it can also modify headers in server responses on their way back to the client.

20 Equalizer Installation and Administration Guide

The table below summarizes the basic capabilities of the cluster types supported by Equalizer.

Cluster Type

Introducing Equalizer

Feature

Load balancing policies

Server failure detection (probes)

Persistence Based on IP Using Cookies

Server selection by request content (i.e., Match Rules)

Load balanced protocols

NAT and spoofing Yes

a. Note that some LDAP/LDAPS implementations are UDP-based.

L4 UDP L4 TCP L7 HTTP L7 HTTPS

round robin, static weight, adaptive, fastest response,

least connections, server agent, custom

ICMP, TCP, Server

Agent

No; load is balanced according to

current load balancing policy.

Ideal for

stateless UDP-

based protocols,

such as DNS and

RADIUS; WAP

gateways; NFS

server clusters

that provide a single-system

image.

Ideal for stateful

TCP-based

protocols, such

as HTTP, HTTPS,

SMTP, FTP,

LDAP/LDAPS

and others.

ICMP, TCP, ACV, Server Agent

Yes; load is balanced according to

decisions made by examining request

content.

HTTP HTTPS

Regardless of cluster type, Equalizer uses intelligent load balancing algorithms to determine the best server to receive a request. These algorithms take into account the configuration options set for the cluster and servers, realtime server status information, and information from the request itself. For Layer 7 clusters, user-defined match rules can also be used to determine the route a packet should take.

Load Balancing Configuration

When you configure a virtual cluster, you can select one of the following load-balancing algorithms to control how Equalizer balances the load across your servers:

connections

, server agent, or custom.

round robin, static weight, adaptive, fastest response, least

When you configure the servers in a virtual cluster, you assign an initial weight between 0 and 200 for each server. When you select one of the adaptive load-balancing algorithms (i.e., any algorithm other than round robin), Equalizer uses the servers’ initial weights as a starting point to determine the percentage of requests to route to each server. Each server handles a percentage of the total load based on its fraction of the total weights in the server cluster. Equalizer dynamically adjusts server weights according to real-time conditions to ensure that Equalizer routes requests to the server that is best able to respond. A server with a weight of zero (0) is considered down or unavailable, and Equalizer does not route requests to servers in this state.

Real-Time Server Status Information

Equalizer gathers real-time information about a server’s status using ICMP Probes, TCP Probes, Active Content Verification (ACV), and Server Agents. ICMP and TCP Probes are the default probing methods.

Equalizer Installation and Administration Guide 21

Chapter 1: Equalizer Overview

ICMP Probes uses the Internet Control Message Protocol to send an "Echo request" to the server, and then wait for the server to respond with an ICMP "Echo reply" message (like the Unix ping command). ICMP is a Layer 3 protocol. ICMP probes can be disabled via a global flag.

TCP Probes establish (and tear down) a TCP connection between Equalizer and the server, in a typical Layer 4 exchange of TCP SYN, ACK, and FIN packets. If the connection cannot be completed, Equalizer considers the server down and stops routing requests to it. TCP probes cannot be disabled.

Equalizer’s Active Content Verification (ACV) provides an optional method for checking the validity of a server’s response using Layer 7 network services that support a text-based request/response protocol, such as HTTP. When you enable ACV for a cluster, Equalizer requests data from each server in the cluster (using an ACV Probe string) and verifies the returned data (against an ACV Response string). If Equalizer receives no response or the response string is not in the response, the verification fails and Equalizer stops routing new requests to that server. (Note that ACV is not supported for Layer 4 UDP clusters.) For more information, see “Using Active Content Verification (ACV)” on page 134.

Server Agent Probes are an optional feature that enable Equalizer to communicate with a user-written program (the agent) running on the server. A server agent is written to open a server port and, when Equalizer connects to the

port, the server agent responds with an indication of the current server load and performance. This enables Equalizer to adjust the dynamic weights of the server according to detailed performance measurements performed by the agent, based on any metrics available on the server. If the server is overloaded and you have enabled server agent load balancing, Equalizer reduces the server’s dynamic weight so that the server receives fewer requests. The interface between Equalizer and server agents is simple and well-defined. Agents can be written in any language supported on the server (e.g., perl, C, shell script, javascript, etc.). For more information see “Server Agent Probes” on page 255.

For those who have one or more VMware ESX Servers, Equalizer VLB can be configured to use VMware’s status reporting to determine server status, and can also be configured to automatically manage VMware servers based on status information obtained from VMware. For more information, see Appendix F, ”Equalizer VLB”.

Network Address Translation and Spoofing

The servers load balanced by Equalizer provide applications or services on specific IP addresses and ports, and are organized into virtual clusters, each with its own IP address. Clients send requests to the cluster IP addresses on Equalizer (instead of sending them to the IP addresses of the servers).

Central to the operation of any load balancer is the Network Address Translation (NAT) subsystem. On Equalizer, NAT is used in the following ways:

1. When Equalizer receives a client packet, it always translates the destination IP (the cluster IP) to the IP address of one of the servers in the cluster. The server IP used is determined by the cluster’s load balancing settings.

2. Depending on the setting of the cluster

When the

spoof option is enabled, then SNAT is disabled: the NAT subsystem leaves the client IP address as

the source IP address in the packet it forwards to the server. For this reason, the servers in a cluster with enabled are usually configured to use Equalizer’s IP as their default gateway, to ensure that all responses go through Equalizer (otherwise, the server would attempt to respond directly to the client IP).

When the

spoof option is disabled, then SNAT is enabled. Equalizer translates the source IP (the client IP) to

one of Equalizer’s IP addresses before forwarding packets to a server. The servers will send responses back to Equalizer’s IP (so it is usually not necessary to set Equalizer as the default gateway on the servers when is disabled).

spoof option, Equalizer may also perform Source NAT, or SNAT.

spoof

Match rules can be used to selectively apply the selective SNAT. See the section “Changing the Spoof (SNAT) Setting Using Match Rules” on page 231.

3. When a server sends a response to a client request through Equalizer, the NAT subsystem always translates the source IP in the response packets (that is, the server IP) to the cluster IP to which the client originally sent the

22 Equalizer Installation and Administration Guide

spoof option to client requests. This is sometimes called

Introducing Equalizer

request. This is necessary since the client sent its original request to the cluster IP and will not recognize the server’s IP address as a response to its request -- instead, it will drop the packet.

4. NAT can also be enabled for packets that originate on the servers behind Equalizer and are destined for subnets other than the subnet on which the servers reside -- on Equalizer, this is called outbound NAT. This is usually required in dual network mode when reserved IP addresses (e.g., 10.x.x.x, 192.168.x.x) are being used on the internal interface, so that the recipients do not see reserved IP addresses in packets originating from the servers. When the global

outbound NAT option is enabled, Equalizer translates the source IP in packets from the servers

that are not part of a client connection to the Equalizer’s Default VLAN IP address (the external interface IP address on the E250GX and legacy ‘si’ systems), or to the address specified in the server’s Enabling

outbound NAT, as a result, has a performance cost since Equalizer is examining every outbound

Outbound NAT tab.

packet.

Note – When Equalizer is in single network mode, outbound NAT should be disabled. Since Equalizer resides on a single subnet, outbound NAT is not needed, and may cause unexpected behavior. See “Adding Equalizer to Your Network” on page 29 for a description of Equalizer’s network modes.

Note that when Equalizer receives a packet that is not destined for a virtual cluster IP address, a failover IP address, a client IP address on an open connection, or one of its own IP addresses, Equalizer passes the packet through to the destination network unaltered.

For more information:

• about setting NAT and spoofing options, see “Working with Virtual Clusters” on page 112.

• about using reserved, non-routing IP addresses with Equalizer, see Appendix C, ”Using Reserved IP

Addresses” on page 271.

Maintaining Persistent Sessions and Connections

The persistence of session data is important when a client and server need to refer to data previously generated again and again as they interact over more than one transaction, possibly more than one connection. Whenever a client places an item in a shopping cart, for example, session data (the item in the cart, customer information, etc.) is created that potentially needs to persist across many individual TCP connections before the data is no longer needed and the session is complete.

It’s important to note that session persistence is managed by the server application, not Equalizer. Equalizer provides server persistence so that a persistent connection between a particular client and a particular server can be maintained; this supports a client-server session where session data is being maintained on the server for the life of the connection. In other words, whether you need to enable persistence on Equalizer depends on the application you are load balancing.

Equalizers have no knowledge of the fact that the user has placed something in a shopping cart, logged into a web application, requested a file from shared storage, or made a "post" in a front end presentation server that has been written to a database. Basically, a "state" has been created in the load balanced application of which Equalizer is not aware. What Equalizer does know is that a specific client has been load balanced to a specific server in one of its virtual clusters. With this knowledge, Equalizer can track that information and send that client back to the same server they were connected the first time.

Equalizer provides server or connection persistence using cookies in Layer 7 HTTP and HTTPS clusters, and using the client IP address in Layer 4 TCP and UDP clusters. The following sections explain connection persistence provided by Equalizer, and its relationship to session persistence.

Cookie-Based Persistence (Layer 7)

Equalizer can use cookie-based persistent connections for Layer 7 HTTP and HTTPS clusters. In cookie-based persistence, Equalizer "stuffs" a cookie into the server's response header on its way back to the client. This cookie

Equalizer Installation and Administration Guide 23

Chapter 1: Equalizer Overview

uniquely identifies the server to which the client was just connected. The client includes (sends) the cookie in subsequent requests to the Equalizer. Equalizer uses the information in the cookie to route the requests back to the same server.

Equalizer can direct requests from a particular client to the same server, even if the connection is to a different virtual cluster. For example, if a user switches from an HTTP cluster to an HTTPS cluster, the persistent cookie will still be valid if the HTTPS cluster contains a server with the same IP address.

If the server with which a client has a persistent session is unavailable, Equalizer automatically selects a different server. Then, the client must establish a new session; Equalizer stuffs a new cookie in the next response.

IP-Address Based Persistence (Layer 4)

For Layer 4 TCP and UDP clusters, Equalizer supports IPaddress based persistent connections. With the sticky connection feature enabled, Equalizer identifies clients by their IP addresses when they connect to a cluster.

Equalizer then routes requests received from a particular client during a specified period of time to the same server in the cluster.

A sticky timer measures the amount of time that has passed since there was a connection from a particular IP address to a specific cluster. The sticky time period begins to expire as soon as there are no longer any active connections between the client and the selected cluster. Equalizer resets the timer whenever a new connection occurs. If the client does not establish any new connections to the same cluster, the timer continues to run until the sticky time period expires. At expiration, Equalizer handles any new connection from that client like any other incoming connection and routes it to an available server based on the current load balancing policy.

To correctly handle sticky connections from ISPs that use multiple proxy servers to direct user connections, Equalizer supports sticky network aggregation, which uses only the network portion of a client's IP address to maintain a persistent connection. Sticky network aggregation directs the user to the same server no matter which proxy he or she connects through.

You can also configure Equalizer to ensure that it directs requests from a particular client to the same server even if the incoming connection is to a different virtual cluster. When you enable intercluster stickiness for a cluster, Equalizer checks the cluster for a sticky record as it receives each connection request, just like it does for ordinary sticky connections. If Equalizer does not find a sticky record, Equalizer proceeds to check all of the other clusters that have the same IP address. If Equalizer still does not find a sticky record, it connects the user based on the current load balancing policy.

Is Connection Persistence Always Needed With Session Persistence?

Session persistence is a function of the application and the state created when a user logs into a web site. If the session persistence is maintained in the front end server, then Equalizer cookie persistence should be enabled. The client must maintain the connection to the same front end server in order for the login to remain valid. For example, Windows Terminal Services maintains a session directory "database" when a user logs into a session. If that state or database is in the front end server, or even in a back end server that only associates the client connection to that front end server, then the client must "persist" to the front end server to which it is originally connected.

In other configurations, the session "state" is kept in shared storage in a backend server or database that is accessible to all the front end servers. If this is the case, then connection persistence may not be needed; if the user is balanced among servers, then the session can still be maintained across the front end server group via access to the shared storage.

It’s therefore important to understand how the load balanced application provides session persistence when managing persistent connections on Equalizer.

Layer 7 Load Balancing and Server Selection

Equalizer’s support for Layer 7 content-sensitive load balancing enables administrators to define rules for routing HTTP and HTTPS requests, depending on the content of the request. Layer 7 load balancing routes requests based

24 Equalizer Installation and Administration Guide

Introducing Equalizer

Internet

Envoy Site A

Envoy

Site B

on information from the application layer. This provides access to the actual data payloads of the TCP/UDP packets exchanged between a client and server. For example, by examining the payloads, a program can base load-balancing decisions for HTTP requests on information in client request headers and methods, server response headers, and page data.

Equalizer’s Layer 7 load balancing allows administrators to define rules in the administration interface for routing HTTP and HTTPS requests according to the request content. These rules are called match rules. A match rule might, for example, route requests based on whether the request is for a text file or a graphics file:

•

load balance all requests for text files (html, etc.) across servers A and B

• load balance all requests for graphics files across servers C, D, and E

• load balance all other requests across all of the servers

Match Rules are constructed using match functions that make decisions based on the following:

• HTTP protocol version; for HTTPS connections, the SSL protocol level the client uses to connect.

• Client IP address

• Request method (GET, POST, etc.)

• All elements of the request URI (host name, path, filename, query, etc.)

• Pattern matches against request headers

Match functions can be combined using logical constructs (AND, OR, NOT, etc.) to create extremely flexible cluster configurations. Please see “Using Match Rules” on page 207 for an overview of Match Rules, a complete list of match functions, and usage examples.

Geographic Load Balancing

The optional Envoy add-on supports , which enables requests to be automatically distributed across Equalizer sites in different physical locations. An Equalizer site is a cluster of servers under a single Equalizer’s control. A is a collection of sites that provide a common service, such as Web sites. The various sites in a geographic cluster can be hundreds or even thousands of miles apart. For example, a geographic cluster might contain two sites, one in the eastern U.S. and one on the U.S.’s west coast (Figure 1).

Geographic load balancing can dramatically improve reliability by ensuring that your service remains available even if a site-wide failure occurs. Equalizer can also improve performance by routing requests to the location with the least network latency.

Figure 1 Geographic cluster with two sites

Equalizer Installation and Administration Guide 25

Chapter 1: Equalizer Overview

Geographic Load Balancing Routing

Envoy routes each incoming request to the site best able to handle it. If a site is unavailable or overloaded, Envoy routes requests to the other sites in the geographic cluster. When you enable geographic load balancing, Envoy directs incoming client requests to one of the sites in the geographic cluster based on the following criteria:

• Availability: If a site is unavailable due to network outage, server failure, or any other reason, Equalizer stops directing requests to that site.

• Performance: Envoy tracks the load and performance at each site and uses this information to determine the site that can process the request most efficiently.

• Distance: Envoy notes the site that is closest to the client (in network terms) and offers the least network latency.

Distributing the Geographic Load

Envoy uses the Domain Name System (DNS) protocol1 to perform its geographic load distribution. DNS translates fully-qualified domain names such as Internet. For Envoy, the authoritative name server for the domain is configured to query the Equalizers in the geographic cluster to resolve the domain name. When Envoy receives a resolution request, it uses the load-balancing algorithms configured for the geographic cluster to determine the site that is best able to process the request and then returns the address of the selected site.

www.coyotepoint.com into the IP addresses that identify hosts on the

For example, the geographic cluster

www.coyotepoint.com might have three sites (see Figure 2): one on the east

coast of the U.S., one on the west coast of the U.S., and one in Europe. The servers at each site are connected to an Equalizer with the Envoy add-on installed.

Envoy Site C

(Europe)

Internet

Envoy Site A

(East Coast USA)

Envoy Site B

(West Coast USA)

Figure 2 Three-site geographic cluster configuration

When a client in California attempts to connect to coyotepoint.com:

1. For more information about DNS, see Paul Albitz and Cricket Liu, DNS and BIND, 3rd ed. (O'Reilly & Associates, 1998).

26 Equalizer Installation and Administration Guide

1. The client queries its local DNS server to resolve the domain name (see Figure 3).

Envoy Site B

(West Coast USA)

Envoy Site A

(East Coast USA)

Internet

Envoy Site C

(Europe)

Client

(California, USA)

Client’s

Local DNS

Authoritative

DNS

for

coyotepoint.com

Envoy Site B

(West Coast USA)

Envoy Site A

(East Coast USA)

Internet

Envoy Site C

(Europe)

Client

(California, USA)

Client’s

Local DNS

Authoritative

DNS

for

coyotepoint.com

Introducing Equalizer

Figure 3 Client queries its local DNS for coyotepoint.com

2. The local DNS server queries the authoritative name server for coyotepoint.com (see Figure 4).

Figure 4 Client’s local DNS queries the authoritative name server for coyotepoint.com

Equalizer Installation and Administration Guide 27

Chapter 1: Equalizer Overview

Envoy Site B

(West Coast USA)

Envoy Site A

(East Coast USA)

Internet

Envoy Site C

(Europe)

Client

(California, USA)

Client’s

Local DNS

Authoritative

DNS

for

coyotepoint.com

3. The authoritative name server provides a list of Envoy-enabled Equalizer sites and returns this list to the client’s local DNS server (see Figure 5).

Figure 5 The authoritative name server for coyotepoint.com returns a list of delegates

4. The client’s DNS server sends a request for the IP address of coyotepoint.com to each Envoy site in the list until one of them responds.

5. The Envoy site contacted returns the IP Address of the virtual cluster best able to handle the client’s request.

6. Finally, the client’s local DNS server returns the virtual cluster IP to the client, which then sends the request to

(For an overview of how Envoy chooses the virtual cluster IP to return to the client’s DNS, see “Administering GeoClusters” on page 237.)

the virtual cluster.

28 Equalizer Installation and Administration Guide

Adding Equalizer to Your Network

Serial Port

External Interface Port

Internal Interface Port

Adding Equalizer to Your Network

Equalizer is a versatile traffic management and application acceleration solution that is easily configured for your network. Equalizer models E350GX and above have 12 or more front panel network switch ports, are Virtual Local Network (VLAN) capable, and can be configured for tagged and untagged VLANs. Equalizer model E250GX has two front panel ports configured into two port based VLANs.

Note – VLAN management capabilities were introduced in Version 8.6 of the Equalizer O/S software on Equalizer GX hardware. If you are running Version 8.6 or later on pre-GX Equalizer hardware (such as the ‘si-R’ hardware), the front-panel switches are managed as they were in Version 8.5 of the Equalizer software. Please refer to the Version 8.5 Installation and Administration Guide at docs.coyotepoint.com.

Equalizer E250GX Network Configuration

Equalizer model E250GX has two front-panel network interface ports configured into two untagged (or port-based) Virtual Local Networks (VLANs): the External Network VLAN and the Internal Network VLAN. Initial network configuration of Equalizer is performed over the serial port, where you assign an IP address to one or both of the network interface ports. The figure below shows the port configuration of an E250GX model Equalizer.

Figure 6 Equalizer E250GX default port configuration

The E250GX can be deployed in either a single network or a dual network configuration:

•In a single network configuration, all cluster IPs and server IPs are on the same subnet, and are connected to Equalizer using the Internal Interface Port; the External Interface Port is unused.

•In a dual network configuration, all cluster IPs are on one subnet connected to Equalizer using the External Interface Port, while servers are on another subnet connected to Equalizer’s Internal Interface Port.

Equalizer Installation and Administration Guide 29

Chapter 1: Equalizer Overview

Using Equalizer E250GX in a Single Network Environment

In single network mode, the client systems, servers, Intranet and/or Internet must all connect to Equalizer through the Internal Interface Port. Figure 7 shows an example.

Figure 7 Example single network configuration for Equalizer E250GX

Single network mode is often the simplest way to fit Equalizer into an existing network with minimal changes to the current network infrastructure. Certain protocols and applications that use dynamic port mapping or multiple TCP/ UDP ports may also work best in a single network environment.

As you can see in the example above, Equalizer’s internal IP, cluster IP, and all server IPs are located on the

192.168.0.x network, and communicate through the same switch. The switch, in turn, is connected to a router which is this subnet’s gateway to other subnets on the Intranet and Internet networks. The gateway or router that conects Equalizer’s subnet to the Intranet and Internet is assumed to perform all necessary NAT for external clients, so they can access Equalizer’s cluster IPs.

Internal clients can access the cluster IPs directly, and so may require selective SNAT on Equalizer or special routing on the servers to ensure that all server responses go through Equalizer.

30 Equalizer Installation and Administration Guide

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