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H3C LS-5100-24P-EI-OVS, LS-5100-50C-EI-OVS, LS-5100-8P-PWR-EI-OVS, LS-5100-8P-SI-OVS-H3, LS-S3100-16C-SI-DC-OVS Configuration

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DHCP H3C Low-End Ethernet Switches Configuration Examples Table of Contents
i
Table of Contents
Chapter 1 DHCP Functions Overview .........................................................................................1-1
1.1 Supported DHCP Functions ..............................................................................................1-1
1.2 Configuration Guide...........................................................................................................1-2
Chapter 2 Configuration Examples .............................................................................................2-1
2.1 DHCP Server Configuration Example................................................................................2-1
2.2 DHCP Relay Agent/Snooping Configuration Examples ....................................................2-4
2.3 Precautions......................................................................................................................2-11
Chapter 3 Related Documents..................................................................................................... 3-1
3.1 Protocols and Standards ...................................................................................................3-1
DHCP H3C Low-End Ethernet Switches Configuration Examples Abstract
ii
DHCP Configuration Examples
Keywords: DHCP, Option 82
Abstract: This document describes DHCP configuration and application on Ethernet
switches in specific networking environments. Based on the different roles played by the devices in the network, the functions and applications of DHCP server, DHCP relay agent, DHCP snooping, and DHCP Option 82 are covered.
Acronym: DHCP (Dynamic Host Configuration Protocol).
DHCP H3C Low-End Ethernet Switches Configuration Examples Chapter 1 DHCP Functions Overview
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Chapter 1 DHCP Functions Overview
1.1 Supported DHCP Functions
1.1.1 DHCP Functions Supported by the H3C Low-End Ethernet Switches
Table 1-1 DHCP functions supported by the H3C low-end ethernet switches
Function
Model
DHCP server
DHCP relay
agent
DHCP snooping
S3600-EI
z
z
z
S3600-SI —
z
z
S5600
z
z
z
S3610
z
z
z
S5510
z
z
z
S5500-SI —
z
z
S5100 — —
z
S3100 — —
z
Depending on the models, the H3C low-end switches can support part or all of the following DHCP functions:
DHCP server:
z DHCP server using global address pool/interface address pool z IP address lease configuration z Allocation of gateway addresses, DNS server addresses, WINS server addresses
to DHCP clients
z Static bindings for special addresses z DHCP server security functions: detection of unauthorized DHCP servers and
detection of duplicate IP addresses
DHCP relay agent:
z DHCP relay agent z DHCP relay agent security functions: address checking , DHCP server handshake,
and periodic update of client address entries
z DHCP Option 82
DHCP snooping:
z DHCP snooping
DHCP H3C Low-End Ethernet Switches Configuration Examples Chapter 1 DHCP Functions Overview
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z DHCP snooping security functions: DHCP snooping entry update and ARP source
checking
z DHCP Option 82
Note:
Refer to respective user manuals for detailed descriptions of the DHCP functions supported by different models.
1.2 Configuration Guide
Note:
z The configuration varies with product models. The following configuration take s the
S3600 series as an example. Refer to respective operation manuals for the configurations on other models.
z Only basic configuration steps are listed below. Refer to respective operation and
command manuals for the operating principles and applications of the functions.
1.2.1 Configuring the DHCP Server
The DHCP server can be configured to assign IP addresses from a global or interface address pool. These two configuration methods are applicable to the following environments:
z If the DHCP server and DHCP clients are on the same network segment, both
methods can be applied.
z If the DHCP server and DHCP clients are on different network segments, the
DHCP server can only be configured to assign IP addresses from a global address pool.
1) Use the following commands to configure the DHCP server to assign IP addresses from a global address pool.
Table 1-2 Configure IP address allocation from a global address pool
Operation Command Description
Enter system view
system-view
—
Enable the DHCP service
dhcp enable
Optional By default, the DHCP
service is enabled.
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Operation Command Description
Create a DHCP address pool and enter DHCP address pool view
dhcp server ip-pool pool-name
Required By default, no global
DHCP address pool is created.
Configure an IP address range for dynamic allocation
network ip-address [ mask-length | mask mask ]
Required By default, no IP
address range is configured for dynamic allocation.
Configure the lease period of dynamically allocated IP addresses
expired { day day [ hour hour [ minute minute ] ] | unlimited }
Optional IP address lease
period defaults to one day.
Configure a domain name for DHCP clients
domain-name domain-name
Required By default, no
domain name is configured for DHCP clients.
Configure DNS server addresses for DHCP clients
dns-list ip-address&<1-8>
Required By default, no DNS
server addresses are configured.
Configure WINS server addresses for DHCP clients
nbns-list ip-address&<1-8>
Required By default, no WINS
server addresses are configured.
Specify a NetBIOS node type for DHCP clients
netbios-type { b-node | h-node | m-node | p-node }
Optional By default, the DHCP
clients are h-nodes if the command is not specified.
Configure gateway addresses for DHCP clients
gateway-list ip-address&<1-8>
Required By default, no
gateway address is configured.
Configure a self-defined DHCP option
option code { ascii ascii-string | hex hex-string&<1-10> | ip-address ip-address&<1-8> }
Required By default, no
self-defined option is configured.
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Operation Command Description
Return to system view
quit
Create an address pool for the static address binding
dhcp server ip-pool pool-name
Specify the IP address of the static binding
static-bind ip-address
ip-address [ mask-length | mask mask ]
Specify the MAC address of the static binding
static-bind mac-address mac-address
Confi gure a static bindi ng
Spe cify the MA C addr ess or the clie nt ID of the stati c bind ing
Specify the client ID of the static binding
static-bind client-identifier client-identifier
Optional By default, no MAC
address or client ID is bound to an IP address statically.
Note:
z To configure a
static binding, you need to specify the IP address and the MAC address or client ID.
z A static address
pool can be configured with only one IP address-to-MAC or IP address-to-client ID binding.
Return to system view
quit
—
Specify the IP addresses to be excluded from automatic allocation
dhcp server forbidden-ip
low-ip-address [ high-ip-address ]
Optional By default, all the IP
addresses in a DHCP address pool are available for dynamic allocation.
interface interface-type interface-number
dhcp select global
On the current interface
quit
Configure the global address pool mode
On multiple interfaces in system view
dhcp select global { interface interface-type interface-number [ to interface-type interface-number ] | all }
Optional By default, an
interface operates in the global address pool mode.
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Operation Command Description
Enable the detection of unauthorized DHCP servers
dhcp server detect
Required By default, the
detection of unauthorized DHCP servers is disabled.
Set the maximum number of ping packets sent by the DHCP server for each IP address
dhcp server ping packets number
Optional The default
maximum number is
2.
Configure duplicate IP address detection
Set a response timeout for each ping packet
dhcp server ping timeout milliseconds
Optional The default timeout
is 500 milliseconds.
Enable the DHCP server to support Option 82
dhcp server relay information enable
Optional By default, the DHCP
server supports Option 82.
2) Use the following commands to configure IP address allocation through the interface address pool.
Table 1-3 Configure IP address allocation through the interface address pool
Operation Command Description
Enter system view
system-view
—
Enable the DHCP service
dhcp enable
Optional By default, the DHCP
service is enabled.
Configure multiple or all the VLAN interfaces to operate in interface address pool mode
dhcp select interface { interface interface-type
interface-number [ to interface-type interface-number ] | all }
Optional
interface interface-type interface-number
Configure a VLAN interface to operate in interface address pool mode
dhcp select interface
Required By default, a VLAN
interface operates in global address pool mode.
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Operation Command Description
Bind an IP address statically to a client MAC address or client ID
dhcp server static-bind ip-address ip-address
{ client-identifier client-identifier | mac-address mac-address }
Optional By default, no static
binding is configured
On the current interface
dhcp server expired { day day [ hour hour [ minute minute ] ] |
unlimited } quit
Config ure the lease period of dynami cally allocat ed IP addres ses
On multiple interfaces in system view
dhcp server expired { day day [ hour hour [ minute minute ] ] | unlimited } { interface
interface-type interface-number [ to interface-type interface-number ] | all }
Optional IP address lease
period defaults to one day.
Return to system view
quit
—
Specify the IP addresses to be excluded from automatic allocation
dhcp server forbidden-ip
low-ip-address [ high-ip-address ]
Optional By default, all the IP
addresses in an interface address pool are available for dynamic allocation.
interface interface-type interface-number
dhcp server domain-name
domain-name
On one interface
quit
Configure a domain name for DHCP clients
On multiple interfaces
dhcp server domain-name
domain-name { interface interface-type interface-number [ to interface-type interface-number ] | all }
Optional By default, no
domain name is configured for DHCP clients.
interface interface-type interface-number
dhcp server dns-list ip-address&<1-8>
On one interface
quit
Configure DNS server addresses for DHCP clients
On multiple interfaces
dhcp server dns-list ip-address&<1-8> { interface interface-type interface-number [ to interface-type interface-number ] | all }
Optional By default, no DNS
server address is configured.
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Operation Command Description
interface interface-type interface-number
dhcp server nbns-list
ip-address&<1-8>
On one interface
quit
Configure WINS server addresses for DHCP clients
On multiple interfaces
dhcp server nbns-list
ip-address&<1-8> { interface interface-type interface-number [ to interface-type interface-number ] | all }
Optional By default, no WINS
server addresses are configured.
interface interface-type interface-number
dhcp server netbios-type { b-node | h-node | m-node | p-node }
On one interface
quit
Define a NetBIOS node type for DHCP clients
On multiple interfaces
dhcp server netbios-type { b-node | h-node | m-node |
p-node } { interface interface-type interface-number [ to interface-type interface-number ] | all }
Optional By default, no
NetBIOS node type is specified and a DHCP client uses the h-node type.
interface interface-type interface-number
dhcp server option code { ascii ascii-string | hex
hex-string&<1-10> | ip-address ip-address&<1-8> }
On one interface
quit
Configure a self-define d DHCP option
On multiple interfaces
dhcp server option code { ascii ascii-string | hex
hex-string&<1-10> | ip-address ip-address&<1-8> } { interface interface-type interface-number [ to interface-type interface-number ] | all }
Optional By default, no
self-defined option is configured.
Enable the detection of unauthorized DHCP servers
dhcp server detect
Optional By default, the
detection of unauthorized DHCP servers is disabled.
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Operation Command Description
Set the maximum number of ping packets sent by the DHCP server for each IP address
dhcp server ping packets
number
Optional The default
maximum number is
2.
Configure duplicate IP address detection
Set a response timeout for each ping packet
dhcp server ping timeout
milliseconds
Optional The default timeout
is 500 milliseconds.
Enable the DHCP server to support Option 82
dhcp server relay information enable
Optional By default, the DHCP
server supports Option 82.
1.2.2 Configuring the DHCP Relay Agent
Use the following commands to configure the DHCP relay agent.
Table 1-4 Configure DHCP relay agent
Operation Command Description
Enter system view
system-view
—
Enable the DHCP service
dhcp enable
Optional By default, the DHCP
service is enabled.
Configure DHCP server IP addresses for a DHCP server group
dhcp-server groupNo ip ip-address&<1-8>
Required By default, no DHCP
server IP address is configured for a DHCP server group.
Configure a DHCP user address entry
dhcp-security static ip-address mac-address
Optional By default, no DHCP user
address entry is configured.
Enable DHCP relay agent handshake
dhcp relay hand enable
Optional By default, DHCP relay
agent handshake is enabled.
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Operation Command Description
Configure the interval at which the DHCP relay agent updates dynamic client address entries
dhcp-security tracker
{ interval | auto }
Optional By default, the update
interval is calculated automatically according to the number of the DHCP client entries.
Enable the detection on unauthorized DHCP servers
dhcp-server detect
Required By default, the detection
of unauthorized DHCP servers is disabled.
Enable the DHCP relay agent to support Option 82
dhcp relay information enable
Required By default, the DHCP
relay agent does not support Option 82.
Configure a strategy for the DHCP relay agent to handle request packets containing Option 82
dhcp relay information strategy { drop | keep | replace }
Optional By default, the strategy is
replace.
Enter VLAN interface view
interface interface-type interface-number
—
Associate the interface to a DHCP server group
dhcp-server groupNo
Required By default, a VLAN
interface is not associated to any DHCP server group.
Enable the address checking function for the DHCP relay agent
address-check enable
Required By default, the address
checking function is disabled for the DHCP relay agent.
1.2.3 Configuring DHCP Snooping
Use the following commands to configure DHCP snooping:
Table 1-5 Configure DHCP snooping
Operation Command Description
Enter system view
system-view
—
Enable DHCP snooping
dhcp-snooping
Required By default, DHCP
snooping is disabled.
Enter Ethernet port view
interface interface-type interface-number
—
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Operation Command Description
Specify the port connected to the DHCP server as a trusted port
dhcp-snooping trust
Optional By default, all the ports of
a switch are untrusted ports.
DHCP H3C Low-End Ethernet Switches Configuration Examples Chapter 2 Configuration Examples
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Chapter 2 Configuration Examples
2.1 DHCP Server Configuration Example
2.1.1 Network Requirements
An S3600 switch serves as the DHCP server in the corporate headquarters (HQ) to allocate IP addresses to the workstations in the HQ and Branch, a nd it also act s as the gateway to forward packets from the HQ. The network requirements are as follows:
z Assign the HQ the IP addresses in the 10.214.10.0/24 network segment, with a
lease period of two days, and exclude the IP addresses of the DNS server, WINS server, and mail server from allocation.
z Assign IP addresses to the DNS server, WINS server, and the mail server in HQ
through static bindings.
z Assign the workstations in the Branch the IP addresses in the 10.210.10.0/24
network segment, with a lease period of three days, and assign the file server in the Branch an IP address through a static IP-to-MAC binding.
z Assign the addresses of the gateway, DNS server, and the WINS server along
with an IP address to each workstation in the HQ and Branch.
z Enable the detection of unauthorized DHCP servers to prevent any unauthorized
DHCP server from allocating invalid addresses.
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2.1.2 Network Diagram
DHCP Relay
Gateway
DHCP
Client
WINS
Server
DNS
Server
Mail
Server
10.214.10.5
002e-8d20-54c6
10.214.10.3
000d-85c7-4e20
10.214.10.4
0013-4ca8-9b71
DHCP
Client1
DHCP
Client2
File Server
10.210.10.4
000d-88f8-4e71
Branch
HQ
IP network
VLAN-int10
VLAN-int100
Figure 2-1 Network diagram for DHCP server configuration
2.1.3 Configuration Procedure
I. Software Version Used
The S3600 Ethernet switches running software version Release 1510 are used in this example.
II. Configuring DHCP server
z Configure address allocation for the devices in the HQ.
# Configure the IP address of VLAN-interface10 on the DHCP server in the HQ.
<H3C> system-view [H3C] interface Vlan-interface 10 [H3C-Vlan-interface10] ip address 10.214.10.1 24
# Configure the interface to operate in the interface address pool mode, assigning the IP addresses in the 10.214.10.0/24 network segment to the devices in the HQ.
[H3C-Vlan-interface10] dhcp select interface
# Configure the address lease period of the address pool, and configure the IP addresses of the DNS server and WINS server.
[H3C-Vlan-interface10] dhcp server expired day 2 [H3C-Vlan-interface10] dhcp server dns-list 10.214.10.3
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[H3C-Vlan-interface10] dhcp server nbst-list 10.214.10.4
No gateway needs to be configured for the clients beca use an interface operating in the interface address pool mode automatically serves as the gateway for DHCP client s and sends the requested information to the clients.
# Assign IP addresses to the DNS server, WINS server, and mail server through IP-to-MAC bindings.
[H3C-Vlan-interface10] dhcp server static-bind ip-address 10.214.10.3 mac-address 000d-85c7-4e20 [H3C-Vlan-interface10] dhcp server static-bind ip-address 10.214.10.4 mac-address 0013-4ca8-9b71 [H3C-Vlan-interface10] dhcp server static-bind ip-address 10.214.10.5 mac-address 002e08d20-54c6
# Exclude the static IP addresses of the DNS server , WINS server , and mail server from allocation.
[H3C-Vlan-interface10] quit [H3C] dhcp server forbidden-ip 10.214.10.3 10.214.10.5
z Configure address allocation for the devices in the Branch.
# Create a global address pool named “br” for the Branch, and specify the range and lease period of the IP addresses for allocation.
[H3C] dhcp server ip-pool br [H3C-dhcp-pool-br] network 10.210.10.0 mask 255.255.255.0 [H3C-dhcp-pool-br] expired day 3
# Create a static binding address pool named “br-static”, and assign the file server in the Branch an IP address through an IP-to-MAC binding.
[H3C-dhcp-pool-br] quit [H3C] dhcp server ip-pool br-static [H3C-dhcp-pool-br-static] static-bind ip-address 10.214.10.4 mask
255.255.255.0
[H3C-dhcp-pool-br-static] static-bind mac-address 000d-88f8-4e71
# Specify the gateway address, DNS server address, and the WINS serve r address for the workstations in the Branch.
[H3C-dhcp-pool-br-static] quit [H3C] dhcp server ip-pool br [H3C-dhcp-pool-br] gateway-list 10.210.10.1 [H3C-dhcp-pool-br] dns-list 10.214.10.3 [H3C-dhcp-pool-br] nbst-list 10.214.10.4
# Exclude the static IP address of the gateway in the Branch from allocation.
[H3C-dhcp-pool-br] quit [H3C] dhcp server forbidden-ip 10.210.10.1
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# Enable the detection of unauthorized DHCP servers.
[H3C] dhcp server detect
# Configure VLAN-interface100 to operate in the global address pool mode.
[H3C] interface Vlan-interface 100 [H3C-Vlan-interface100] dhcp select global
Note that: After DHCP configuration is complete, IP addresses can be assigned to the
workstations in the Branch only when a route is active between the HQ an d the Branch.
III. Configuring the DHCP relay agent
This section mainly describes the DHCP server configuration. The following shows the basic DHCP relay agent configuration that ensures the DHCP relay agent to relay DHCP requests to the DHCP server. For details about DHCP relay agent configuration, see section
2.2 "DHCP Relay Agent/Snooping Configuration Examples".
<H3C> system-view [H3C] dhcp-server 1 ip 10.214.10.1 [H3C] interface Vlan-interface 5 [H3C-Vlan-interface5] dhcp-server 1
2.2 DHCP Relay Agent/Snooping Configuration Examples
2.2.1 Network Requirements
A Cisco Cat al y st 3745 swit ch i s depl oye d in the HQ and serves a s the DHCP server to assign IP addresses to the workstations in the Office branch. The branches are connected to an IRF (intelligent resilient framework) Fabric that serves as the central node and the DHCP relay agent to forward the DHCP requests from the workstations. Meanwhile, a lab DHCP server is used to assign IP addresses to the devices in the labs. The network requirements are as follows:
z Configure the DHCP server in the HQ to assign the IP addresses in the
192.168.10.0/24 network segment to the workstations in the Office branch, with a lease period of 12 hours. Configure the IP addresses of the DNS server and WINS server as 192.169.100.2 and 192.168.100.3 respectively.
z The IRF Fabric is connected to the branches and is comprised of four switches. It
serves as the DHCP relay agent to forward the DHCP requests from the workstations in the Office and the devices in the labs. It is enabled to detect unauthorized DHCP servers.
z An Ethernet switch in Lab1 serves as the Lab DHCP server to assign the IP
addresses in the 192.168.17.0/24 network segment to the devices in Lab1, with a lease period of one day, and to assign the IP addresses in the 192.168.19.0/24 network segment to Lab2, with a lease period of two days. The lab DHCP server
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and the IRF Fabric are interconnected through the 172.16.2.4/30 network segment.
z Configure the address checking function on the DHCP relay agent so that only the
devices that are assigned legal IP addresses from the DHCP server are allowed to access the external network.
z Configure address entry update on the DHCP relay agent so that it updates the
address entries by sending requests to the DHCP server every one minute.
z Enable DHCP snooping to support DHCP Option 82, adding local port information
to the Option 82 field in DHCP messages.
z Enable the DHCP relay agent to support DHCP Option 82 so that the DHCP relay
agent keeps the original filed unchanged upon receiving DHCP messages carrying Option 82.
z Enable the DHCP server to support DHCP Option 82 so that it assigns the IP
addresses 192.168.10.2 through 192.168.10.25 to the DHCP clients conne cted to Ethernet1/0/11 on the DHCP snooping switch and assigns 192.168.10.100 through 192.168.10.150 to the DHCP clients connected to Ethernet1/0/12 of the DHCP snooping switch.
2.2.2 Network Diagram
IP network
SwitchA (Master)
SwitchB
(Unit2)
SwitchC
(Unit3)
SwitchD
(Unit4)
VLAN-int 10
192.168.10.1
Eth1/0/1
Eth1/0/11
Eth1/0/12
Eth1/0/13
VLAN-int 17
172.16.2.4/30 VLAN-int 15
192.168.17.1
0010-5ce9-1dea
IRF Fabric
DHCP Relay
VLAN-int 25
192.168.19.1
Lab2
HQ
Office Lab1
Lab DHCP Server
DHCP Snooping
Cisco Catalyst
3745
192.168.0.3
Figure 2-2 Network diagram for DHCP relay agent/snooping integrated configuration
DHCP H3C Low-End Ethernet Switches Configuration Examples Chapter 2 Configuration Examples
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2.2.3 Configuration Procedure
In this example, the IRF Fabric is comprised of S3600 switches running software version Release 1510, a Quidway S3552 switch running software version Release 0028 is used as the DHCP snooping-capable switch, and a Quidway S3528 switch running software version Release 0028 is used as the Lab DHCP server.
For better readability:
z The devices in the IRF Fabric are SwitchA, SwitchB, SwitchC, and SwitchD. z The DHCP snooping-capable device is referred to as “Snooping”. z The device serving as the Lab DHCP server is referred to as “LAB”.
I. Configuring IRF Fabric
The S3600 series support IRF Fabric. You can interconnect four devices to form a Fabric for centralized management of the devices in the Fabric. For det ails, see related sections in the operation manuals for the S3600 series.
II. Configuring the DHCP relay agent
Figure 2-3 Network diagram for DHCP relay agent configuration
Within the IRF Fabric, configuration made on a device can be synchronized to the other devices. Therefore, configuration is performed on Switch A only in this example.
# Configure to forward the DHCP requests from the Office to the DHCP server in the HQ.
<SwitchA> system-view [SwitchA] dhcp-server 1 ip 192.168.0.3 [SwitchA] interface vlan-interface10 [SwitchA-Vlan-interface10] ip address 192.168.10.1 24 [SwitchA-Vlan-interface10] dhcp-server 1
# Configure to forward the DHCP requests from Lab2 to the Lab DHCP server.
[SwitchA-Vlan-interface10] quit [SwitchA] dhcp-server 2 ip 192.168.17.1 [SwitchA] interface Vlan-interface 25 [SwitchA-Vlan-interface25] ip address 192.168.19.1 24
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[SwitchA-Vlan-interface25] dhcp-server 2
# Configure the IP address of VLAN-interface17 as 172.16.2.5/30 for forwarding DHCP packets from the Lab DHCP Server to a non-local segment.
[SwitchA-Vlan-interface25] quit [SwitchA] interface Vlan-interface 17 [SwitchA-Vlan-interface17] ip add 172.16.2.5 30
# Configure the address checking function on the DHCP relay agent. Make sure you configure the IP addresses and MAC addresses of the two DHCP servers as static entries for the security function.
[SwitchA-Vlan-interface17] quit [SwitchA] dhcp-security static 192.168.0.3 000D-88F8-4E71 [SwitchA] dhcp-security static 192.168.17.1 0010-5ce9-1dea [SwitchA] interface Vlan-interface 10 [SwitchA-Vlan-interface10] address-check enable [SwitchA-Vlan-interface10] quit [SwitchA] interface vlan-interface 25 [SwitchA-Vlan-interface25] address-check enable [SwitchA-Vlan-interface25] quit
# Configure the address entry update interval on the DHCP relay agent.
[SwitchA] dhcp relay hand enable [SwitchA] dhcp-security tracker 60
# Enable the DHCP relay agent to support DHCP Option 82 and adopt the strategy of keeping the original filed upon receiving DHCP messages carrying Option 82.
[SwitchA] dhcp relay information enable [SwitchA] dhcp relay information strategy keep
# Enable the DHCP relay agent to detect unauthorized DHCP servers.
[SwitchA] dhcp-server detect
# Enable UDP-Helper so that the IRF Fabric can operate in the DHCP relay agent mode.
[SwitchA] udp-helper enable
# To ensure normal forwarding of DHCP packets across network segments, you need configure a routing protocol and advertise the network segments of interfaces. The following configuration uses RIP as an example. For the configuration of other routing protocols, see the parts covering routing protocols in product manuals.
[SwitchA] rip [SwitchA-rip] network 192.168.10.0 [SwitchA-rip] network 192.168.19.0 [SwitchA-rip] network 172.16.0.0
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Note:
For the DHCP relay agent using the IRF structure and the DHCP server in the HQ to communicate with each other, an active route must also be configured between them. This configuration is performed by the ISP or the user; therefore, it will not be covered in this document.
III. Configuring the Lab DHCP server
VLAN-int 15
192.168.17.1
0010-5ce9-1dea
Lab1
VLAN-int 17
172.16.2.4/30
Figure 2-4 Network diagram for the Lab DHCP server configuration
# Configure an address pool for Lab2 and specify the address rang e, lease period, and the gateway address.
<LAB> system-view [LAB] dhcp enable [LAB] dhcp server ip-pool lab2 [LAB-dhcp-lab2] network 192.168.19.0 255.255.255.0 [LAB-dhcp-lab2] expired day 2 [LAB-dhcp-lab2] gateway-list 192.168.19.1
# Configure the IP address of VLAN-interface17 as 172.16.2.6/30 and enable it to operate in global address pool mode.
[LAB-dhcp-lab2] quit [LAB] interface Vlan-interface 17 [LAB-Vlan-interface17] ip address 172.16.2.6 30 [LAB-Vlan-interface17] dhcp select global
# Lab1 is connected to VLAN-interface15. Therefore, to assign the IP addre sses in the
192.168.17.0/24 network segment to the devices in Lab1, you only need to configure VLAN-interface15 to operate in the interface address pool mode.
[LAB-Vlan-interface17] quit [LAB] interface vlan-interface 15 [LAB-Vlan-interface15] ip address 192.168.17.1 24
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[LAB-Vlan-interface15] dhcp select interface [LAB-Vlan-interface15] quit
# To ensure that the lab DHCP server forwards DHCP packets normally, you need configure a routing protocol. The following configuration uses RIP as an example. For the configuration of other routing protocols, see the related parts in product manuals.
[LAB] rip [LAB-rip] network 192.168.17.0 [LAB-rip] network 172.16.0.0
IV. Configuring DHCP snooping
Eth1/0/1
Eth1/0/11
Eth1/0/12
Eth1/0/13
Office
DHCP Snooping
Figure 2-5 Network diagram for DHCP snooping configuration
# Enable DHCP snooping and enable Option 82 support for DHCP snooping.
<Snooping> system-view [Snooping] dhcp-snooping [Snooping] dhcp-snooping information enable [Snooping] dhcp-packet redirect Ethernet 0/11 to 0/13
V. Configuring the DHCP server in the HQ
# On the H3C series switches, port numbers, VLAN numbers, and the MAC addresses of the DHCP snooping device and the DHCP relay agent are added to DHCP Option 82. A complete piece of Option 82 information is a combination of the values of two suboptions:
Circuit ID suboption: It identifies the VLAN to which the clients belong and the port to which the DHCP snooping device is connected.
0 31
Type(1)
15
VLAN ID
Length(6) 0 4
Port Index
Figure 2-6 Packet structure of Circuit ID suboption
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For example, the DHCP messages from clients conne cted to Ethernet1/0/1 1 a re added with Option 82, whose Circuit ID suboption should be 0x010600040001000a, where 01060004 is a fixed value, 0001 indicates the access port’ s VLAN is VLAN 1, and 000a is the absolute number of the port, which is 1 less than the actual port number, indicating the actual port is Ethernet1/0/11.
Remote ID suboption: It identifies the MAC address of the DHCP snooping device connected to the client.
0 31
Type(2)
15
Bridge MAC Address
Length(8) 0 6
Figure 2-7 Packet structure of Remote ID suboption
For example, the DHCP messages from clients connected to the DHCP snooping device with MAC 000f-e234-bc66 are added with Option 82, whose Remote ID suboption should be 02080006000fe234bc66, where 02080006 is a fixed value and 000fe234bc66 is the MAC address of the DHCP snoo ping device.
In this example, IP addresses are assigned based on port number only. Therefore, on the DHCP server , only a matching port number field in the Circuit ID suboption needs to be found.
Note:
The following configuration is performed on the Cisco Catalyst 3745 switch running IOS version 12.3(11)T2. If you are using any other models or devices running any other version, see the user manuals provided with the devices.
# Enable DHCP server and allocate IP addresses using Option 82 information.
Switch> enable Switch(config)# configure terminal Enter Configuration commands, one per line. End with CNTL/Z. Switch(config)# service dhcp Switch(config)# ip dhcp use class
# Create a DHCP class for the client connected to Ethernet1/0/11 of the DHCP snooping device and match the port number in the Circuit ID suboption of Option82, and replace the contents without match need with a wildcard "*".
Switch(config)# ip dhcp class office1 Switch(dhcp-class)# relay agent information hex 010600040001000a*
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Switch(dhcp-class)# exit
# Configure a DHCP class for the client connected to Etherent1/0/12 of the DHCP snooping device and match the port number in the Circuit ID suboption of Option82.
Switch(config)# ip dhcp class office2 Switch(dhcp-class)# relay agent information hex 010600040001000b*
# Create an address pool for Office and specify address ranges for the two DHCP classes.
Switch(config)# ip dhcp pool office Switch(dhcp-pool)# network 192.168.10.0 Switch(dhcp-pool)# class office1 Switch(dhcp-pool-class)# address range 192.168.10.2 192.168.10.25 Switch(dhcp-pool-class)# exit Switch(dhcp-pool)# class office2 Switch(dhcp-pool-class)# address range 192.168.10.100 192.168.10.150 Switch(dhcp-pool-class)# exit
# Configure the lease period, gateway address, DNS server address, and WINS server address for the address pool.
Switch(dhcp-pool)# lease 0 12 Switch(dhcp-pool)# default-router 192.168.10.1 Switch(dhcp-pool)# dns-server 192.168.100.2 Switch(dhcp-pool)# netbios-name-server 192.168.100.3
After the above-mentioned configuration, the DHCP server can automatically assign an IP address, the gateway address, DNS server address, and the WINS server address for each device in Office.
2.3 Precautions
2.3.1 Cooperation Between DHCP Relay Agent and IRF
z In an IRF network, the DHCP relay agent runs on all the units in the Fabric. But
only the DHCP relay agent running on the master unit can receive and send packets to perform full DHCP relay agent functions. The DHCP relay agent running on a slave unit, however, only serves as a backup for the master unit.
z DHCP is an application-layer protocol based on UDP. Once a slave unit receives a
DHCP request, UDP-Helper redirects the packet to the master unit. Then, the DHCP relay agent running on the master unit gives a response back to the request and sends the real time information to each slave unit for backup. In this way, when the current master unit fails, one of the slaves becomes the new master and operates as the DHCP relay agent immediately. Therefore, make sure you enable UDP-Helper before using DHCP relay agent in an IRF system.
DHCP H3C Low-End Ethernet Switches Configuration Examples Chapter 3 Related Documents
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Chapter 3 Related Documents
3.1 Protocols and Standards
z RFC2131: Dynamic Host Configuration Protocol z RFC2132: DHCP Options and BOOTP Vendor Extensions z RFC3046: DHCP Relay Agent Information Option
QACL H3C Low-End Ethernet Switches Configuration Examples Table of contents
i
Table of Contents
Chapter 1 QACL Overview............................................................................................................ 1-1
1.1 Supported QACL Functions...............................................................................................1-1
1.2 Configuration Guide........................................................................................................... 1-3
Chapter 2 Examples of QACL Configuration.............................................................................. 2-1
2.1 Network Environment ........................................................................................................ 2-1
2.2 Time-based ACL plus Rate Limiting plus Traffic Policing Configuration Example............2-2
2.3 Configuration Example of Priority Re-marking plus Queue Scheduling Algorithm plus
Congestion Avoidance plus Packet Priority Trust....................................................................
2-4
2.4 Configuration Example of Traffic Measurement plus Port Redirection.............................. 2-5
2.5 Configuration Example of Local Traffic Mirroring .............................................................. 2-7
2.6 Precautions........................................................................................................................ 2-8
2.7 Other Functions Referencing ACL Rules .......................................................................... 2-9
Chapter 3 Configuration Example of WEB Cache Redirection................................................. 3-1
3.1 Configuration Example of WEB Cache Redirection ..........................................................3-1
QACL H3C Low-End Ethernet Switches Configuration Examples Abstract
ii
QACL Configuration Examples
Key words: ACL, and QoS
Abstract: This document describes QACL configurations on Ethernet switches in actual
networking environments. To satisfy different user needs, the document covers various functions and applications like time-based ACLs, traffic policing, priority re-marking, queue scheduling, traffic measurement, port redirection, local traffic mirroring, and WEB Cache redirection.
Acronyms: Access control list (ACL), and quality of service (QoS)
QACL H3C Low-End Ethernet Switches Configuration Examples Chapter 1 QACL Overview
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Chapter 1 QACL Overview
1.1 Supported QACL Functions
1.1.1 ACL/QoS Functions Supported by H3C Low-End Ethernet Switches
Table 1-1 ACL/QoS functions supported by H3C low-end ethernet switches
Model
Function
S3600-EI S3600-SI S5600 S5100-EI S5100-SI
S3100-
SI
Basic ACL
z
z
z
z
z
z
Advanced ACL
z
z
z
z
z
z
Layer 2 ACL
z
z
z
z
—
—
User-defined ACL
z
z
z
—
—
—
Software-bas ed ACL referenced by upper-layer software
z
z
z
z
z
z
Apply hardware-bas ed ACL to hardware
z
z
z
z
—
—
Traffic classification
z
z
z
z
—
—
Priority re-marking
z
z
z
z
—
—
Port rate limiting
z
z
z
—
z
z
Traffic policing
z
z
z
z
—
—
Traffic shaping
—
—
—
z
—
—
Port redirection
z
z
z
z
—
—
Queue scheduling
z
z
z
z
z
z
Congestion avoidance
z
z
—
—
—
—
QACL H3C Low-End Ethernet Switches Configuration Examples Chapter 1 QACL Overview
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Model
Function
S3600-EI S3600-SI S5600 S5100-EI S5100-SI
S3100-
SI
Local traffic mirroring
z
z
z
z
—
—
Traffic measurement
z
z
z
z
—
—
WEB Cache redirection
z
—
—
—
—
—
Note: z means that the function is supported.
— means that the function is not supported.
Note:
For details on ACL/QoS functions supported by different models, refer to corresponding operation manuals.
QACL H3C Low-End Ethernet Switches Configuration Examples Chapter 1 QACL Overview
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1.2 Configuration Guide
Note:
z ACL/QoS configuration varies with switch models. The configuration below takes an
H3C S3600 Ethernet Switch as an example. For ACL/QoS configuration on other switches, refer to corresponding user manuals.
z The section below only lists basic configuration steps. For the operating principle
and detailed information of each function, refer to the operation manual and command manual of each product.
Table 1-2 Configure ACL/QoS in system view
Configuration Command Remarks
Create an ACL and enter ACL view
acl number acl-number [ match-order { config | auto } ]
By default, the matching order is config.
Layer 2 ACLs and user-defined ACLs do not support match-order.
Define an ACL rule
rule [ rule-id ] { permit | deny } rule-string
The parameters (criteria) available for rule-string vary with ACL types. For details, refer to the corresponding command manual.
Configure a queue scheduling algorithm in system view
queue-scheduler { strict-priority | wfq
queue0-width queue1-width queue2-width queue3-width queue4-width queue5-width queue6-width queue7-width | wrr queue0-weight queue1-weight queue2-weight queue3-weight queue4-weight queue5-weight queue6-weight queue7-weight }
z If the weight or minimum
bandwidth of a queue is set to 0 in the WRR or WFQ approach, strict priority queuing applies to the queue.
z By default, the WRR
queue scheduling algorithm is used for all outbound queues on a port. Default weights are 1:2:3:4:5:9:13:15.
z The queue scheduling
algorithm defined using the queue-scheduler command in system view will work on all ports.
Configure congestion avoidance
wred queue-index qstart probability
—
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Table 1-3 Configure ACL/QoS in port view
Configuration Command Remarks
Apply an ACL on a port
packet-filter { inbound | outbound } acl-rule
—
Configure the switch to trust the priority of received packets
priority trust
Configure the switch to trust the priority carried in received packets.
Configure port-based rate limit
line-rate { inbound | outbound } target-rate
The granularity is 64 kbps. If an entered number is in the range N×64 to (N+1)×64 (N is a natural number), the switch takes the value (N+1)×64.
Reference an ACL for traffic identification, and re-assign a priority to the matching packets
traffic-priority { inbound | outbound } acl-rule { { dscp dscp-value | ip-precedence { pre-value | from-cos } } |
cos { pre-value | from-ipprec } | local-precedence
pre-value }*
You can re-mark the IP priority, 802.1p priority, DSCP priority of packets, and the priority of local queues.
Configure traffic policing
traffic-limit inbound
acl-rule target-rate
[ exceed action ]
exceed action: specifies
the action taken on the excess packets when the packet traffic exceeds the preset limit.
z drop: Drop the
excess packets.
z remark-dscp value:
Re-set the DSCP priority, and forward the packets.
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