Black Box 16 port User Manual
Size:
3.11 Mb
Download

Configuring a dial in line

Introduction to SLIP and PPP connections

This section deals with setting up SLIP and PPP connections on a line. There is also a summary of the configurable features of modems.

Deciding whether to use SLIP or PPP

If you require any of the features listed below, use PPP, otherwise SLIP should be sufficient.

IP Address Negotiation. SLIP provides no mechanism for informing the other end of a link of its IP address, whereas PPP will do so.

Error Checking. SLIP does not error check whereas PPP does. This is not necessarily a problem in SLIP since most upper layer protocols have their own error checking.

Some systems exchange UDP packets with checksum disabled, which would cause problems should that part of an IP packet get corrupted.

Authentication. Once SLIP has started you cannot authenticate the remote device, whereas as PPP provides the option of using security protocols PAP or CHAP. SeeConfiguring PPP on page 82, thensub-section‘Security’ for further details.

Software Flow Control. You cannot use software flow control on SLIP links since there is no way of escaping control characters from the data stream. PPP has a facility (called ACCM) which allows specific control characters to be escaped from the data stream.

See Configuring PPP on page 82 for more details.

For more information on the SLIP and PPP protocols see Configuring a dial in line on page 74.

Black Box Console Server user guide

74

Setting up the line

cli syntax: 1.

From the Line Configuration menu, select ‘Line Settings’.

set line,

2.

Within the Line settings menu, select a particular line; e.g. line 3.

show line

 

 

The line form will be displayed (default values shown in the next example):

3.Within the line form, set the Service field using one of the options given in the next table;

Black Box Console Server user guide

75

Service option

Description

PPPWhen you want a remote access service connection using PPP, or when you want to use the unit as a router with PPP. In both cases the user (whether real or dummy) will be authenticated within PPP (provided you use Security - PAP or CHAP).

cslogin

When you want a remote access service connection using SLIP. Do not use the

 

option ‘SLIP’ because there would be no authentication of the user; (instead,

 

you will set SLIP for a particular user - see Configuring a user account on page

 

100).

 

Choosing the ‘cslogin’ option, the unit will present the login prompt: the user

 

will be required to enter a name and password and hence will be authenticated.

SLIP

When you want to use the unit as a router with SLIP. There will be no

 

authentication of each unit by the other unit.

 

 

Option

Description

 

 

Line name

Line name can be configured to uniquely identify the line.

Speed, Bits,

Change as necessary from the default line configuration of 9600 baud, 8 data

Parity and

bits, no parity, 1 stop bit.

Stop

 

Flow

Flow Control field to either ‘soft’ (software) or ‘hard’ (hardware). For SLIP set to

 

‘hard’ only. For PPP set to either ‘soft’ or ‘hard’ (‘hard’ recommended). If you

 

select ‘soft’ you must set the parameter ACCM when you configure PPP for the

 

line (in Configuring PPP on page 82)

Host port field. This is the host TCP port number and is set by default to 23. In most cases you can use the default value.

Dial

Set to ‘in’ if your user is remote and will be dialling in via modem or ISDN TA;

 

set to ‘in’ or ‘out’ if using the unit as a router, depending on which end of the

 

link your unit is situated.

Phone Number When dial is set to ‘out’ and the line ‘service’ is set to ‘slip’ or ‘ppp’ enter a phone number for the unit to dial (you should only have this combination of settings when you are using two unitsback-to-back,i.e. as routers.

Idle Timer Enter a period in seconds for which the idle timer will run. Use this timer torouter use only close a connection because of inactivity. When the idle timer expires the unit

will end the connection. The default value is 300 seconds, meaning the idle timer will expire 300 seconds after the last activity. The maximum value is 4294967 seconds (equal to 49 days, approximately). A value of 0 (zero) means the idle timer will not expire, so the connection is open permanently.

Black Box Console Server user guide

76

Service option

Description

Session Timer

Enter a period in seconds for which the session timer will run. Use this timer to

router use only

forcibly close the session (connection). When the session timer expires the unit

 

will end the connection. The default value is 0 (zero), meaning that the session

 

timer will not expire (the session is open permanently, or until you kill the line.

 

The maximum value is 4294967 seconds (equal to 49 days, approximately).

 

 

cli syntax: add modem

4.Ignore the other fields in this form. Press <return> to exit; if you do not wish to save your changes press the <escape> key.

5.Now go to the Line Configuration Menu:

6.Within the Line Configuration Menu, select ‘Add Modem’.

7.Enter the name of the modem/ISDN TA attached to the unit. You can enter a maximum of twenty names, each with nineteen alphanumeric characters.

8.Within the Line Configuration Menu, select ‘Change Modem’. Select your modem/ISDN TA name. Enter the initialisation string; see your modem/ISDN TA documentation.

9.Press <return> to exit; if you do not wish to save your changes press the <escape>

key.

set line 10. Go back to the ‘Line Settings’ menu. Select your line. When the line parameters form appears go the field ‘modem name’. Press ‘L’ (upper or lower case) or the spacebar. Choose the modem name which you entered atStep 5.

11.Press <return> to exit; if you do not wish to save your changes press the <escape> key.

You can copy the settings for this line to other lines (an option as you exit this line);

You can reset this line to default (an option as you exit this form); refer to Resetting the line to default on page 111

12.You may want to save your configuration permanently; if so, refer to Saving settings to non-volatile memory on page 112.

Black Box Console Server user guide

77