System Administration Guide: Network Services

Basic Chat Script Enhanced for a UNIX-Style Login

The next chat script is a basic script that is enhanced for calling a remote Solaris peer or other UNIX-type peer. This chat script is used in How to Create the Instructions for Calling a Peer.


        SAY "Calling the peer\n"
        TIMEOUT 10
        ABORT BUSY
        ABORT 'NO CARRIER'
        ABORT ERROR
        REPORT CONNECT
        "" AT&F1&M5S2=255
        TIMEOUT 60
        OK ATDT1-123-555-1234
        CONNECT \c
        SAY "Connected; logging in.\n"
        TIMEOUT 5
        ogin:--ogin: pppuser
        TIMEOUT 20
        ABORT 'ogin incorrect'
        ssword: \qmypassword
        "% " \c
        SAY "Logged in.  Starting PPP on peer system.\n" 
        ABORT 'not found'
        "" "exec pppd"
        ~ \c

The following table explains the parameters of the chat script.

Script Contents 

Explanation 

TIMEOUT 10

Set initial timeout to 10 seconds. The modem's response should be immediate. 

ABORT BUSY

Abort transmission if the modem receives this message from the opposite peer. 

ABORT 'NO CARRIER'

Abort transmission if the modem receives this message from the opposite peer. 

ABORT ERROR

Abort transmission if the modem receives this message from the opposite peer. 

REPORT CONNECT

Gather the CONNECT string from the modem. Print the string.

"" AT&F1&M5S2=255

&M5 – Make the modem require error control.

S2=255 – Disable the TIES “+++” break sequence.

TIMEOUT 60

Reset the timeout to 60 seconds to allow more time for link negotiation. 

OK ATDT1-123-555-1234

Call the remote peer by using the phone number 123-555-1212. 

CONNECT \c

Wait for the CONNECT message from the opposite peer's modem.

SAY "Connected; logging in.\n"

Display the informative message Connected; logging in to give the user status.

TIMEOUT 5

Change the timeout to enable quick display of the login prompt. 

ogin:--ogin: pppuser

Wait for the login prompt. If the prompt is not received, send a RETURN and wait. Then, send the user name pppuser to the peer. The sequence that follows is referred to by most ISPs as the PAP login. However, the PAP login is not related in any way to PAP authentication.

TIMEOUT 20

Change the timeout to 20 seconds to allow for slow password verification. 

ssword: \qmysecrethere

Wait for the password prompt from the peer. When the prompt is received, send the password \qmysecrethere. The \q prevents the password from being written to the system log files.

"% " \c

Wait for a shell prompt from the peer. The chat script uses the C shell. Change this value if the user prefers to log in with a different shell. 

SAY "Logged in. Starting PPP on peer system.\n"

Display the informative message Logged in. Starting PPP on peer system to give the user status.

ABORT 'not found'

Abort the transmission if the shell encounters errors. 

"" "exec pppd"

Start pppd on the peer.

~ \c

Wait for PPP to start on the peer. 

Starting PPP right after the CONNECT \c is often called a PAP login by ISPs, though the PAP login is actually not part of PAP authentication.

The phrase ogin:--ogin: pppuser instructs the modem to send the user name pppuser in response to the login prompt from the dial-in server. pppuser is a special PPP user account name that was created for remote user1 on the dial-in server. For instructions about creating PPP user accounts on a dial-in server, refer to How to Configure Users of the Dial-in Server.