# 4.5. Login Script

Edit Script

  Use this dialog to compose a dial in script for your ISP dialup connection. Use the mini-terminal and the information supplied by your ISP to understand which sequence of actions needs to be executed.

  - Expect: kppp will wait for the specified string to be received.

  - Send: kppp will send the specified string.

  - Scan: kppp will scan the the input stream for the specified string and store any character after the string up to the first newline in an internal buffer. Trailing and leading whitespace will be stripped off.

  - Save: permanently store the previously scanned string in the specified register. So far, the only valid register is 'password'.

  - Pause: pause for the specified number of seconds

  - Hangup: kppp will send the hangup command to the modem

  - Answer: kppp will set the modem into answer mode

  - Timeout: change the default timeout to the specified number of seconds dynamically during script execution. You can change the timeout several times during script execution if necessary.

  - Prompt: Prompt the kppp user to enter a string, given the specified string as a hint. The user will see what is typed. If the specified string includes the mark ## the mark will be replaced with the current content of the internal scan buffer.

  - PWPrompt: Prompt the kppp user to enter a string, given the specified string as a hint. An asterisk will be printed for each character typed.

  - ID: If the ID field on kppp's main dialog is filled in, send that ID. If the ID field is not filled in, prompt the kppp user to enter an ID, given the specified string as a hint. The user will see what is typed. On a second pass, such as in a loop on the second iteration, a prompt will be displayed, given the specified string as a hint.

  - Password: If the password field on kppp's main dialog is filled in, send that password. If the password field is not filled in, prompt the kppp user to enter a password given the specified string as a hint. An asterisk will be printed for each character typed. On a second pass, such as in a loop on the second iteration, a prompt will be displayed, given the specified string as a hint.

  - LoopStart: kppp will wait for the specified string to be received. It will save the string for use by LoopEnd

  - LoopEnd: kppp will wait for the specified string to be received to exit the loop. If the string given by the corresponding LoopStart is received first, it will trigger a jump to the line after the LoopStart, enabling repetition of username/password style paired dialogs.

## 4.5.1. Example scripts

Here is a simple script I could use to connect to my ISP:

     Expect      ID:                        # wait for ID:
     Send        myid                       # you have to substitute myid with your id
     Expect      word:                      # wait for 'password'
     Send        4u3fjkl                    # send my password '4u3fjkl'
     Expect      granted                    # My ISP send 'Permission granted' on login success.
     Send        ppp                        # This starts a ppp connection for
                                            # me on the ISP side.

Here a script for the same account with ID and password prompt: This script will prompt for ID and password each time, no matter what is typed into the ID and password field on kppp's main dialog. This script also illustrated the use of the LoopStart/LoopEnd structure. If something goes wrong during the login procedure, for example if I mistype the password, my ISP will print an error message and restart the id/password loop by issuing the string "ID:" again. If the string "ID" is caught before the LoopEnd keyword was parsed, kppp will start the script again after the LoopStart keyword.

     LoopStart   ID:                        # wait for ID:
     Prompt      Enter ID:                  # Prompt me for my ID and send it off.
     Expect      word:                      # wait for 'password'
     PWPrompt    Enter Password:            # Prompt me for my password and send it off.
     LoopEnd     granted                    # My ISP send 'Permission granted' on login success.
     Send        ppp                        # This starts a ppp connection for me

Here is the script that I actually use to connect to my ISP: This script will prompt for ID and password only if I haven't filled in the respective fields on kppp's main dialog.

     LoopStart   ID:                        # wait for ID:
     ID          Enter ID:                  # Prompt me for my ID and send it off.
     Expect      word:                      # wait for 'password'
     Password    Enter Password             # Prompt me for my password and send it off.
     LoopEnd     granted                    # My ISP send 'Permission granted' on login success.
     Send        ppp                        # This starts a ppp connection for me
                                            # on the ISP side

Here is a script that I use to connect to an ISP which is using some sort of challenge/response authentication. Usually you got a hardware token (a smart card with a display and calculator like keypad) from the ISP. You have to know a password to use the token. After dialling in your ISP displays your challenge. You have to type in the challenge to your token and get a dynamic password as a response. Then you have to enter that password.

     LoopStart   ID:                        # wait for ID:
     ID          Enter ID:                  # Prompt me for my ID and send it off.
     Scan        Challenge:                 # Scan for 'Challenge' and store everything behind up to the next newline.
     Expect      Password:                  # wait for 'password'
     Prompt      Your token is ## - Enter Password  # Prompt me for my password and send it off.
     LoopEnd     granted                    # My ISP sends 'Permission granted' on login success.
     Send        ppp                        # This starts a ppp connection for me
                                            # on the ISP side

The following log shows the login procedure of a fictitious ISP that provides a new password on each login. The new password has to be verified and recorded for the next session.

     University of Lummerland

     Login:mylogin
     Password:
     The password for your next session is: YLeLfkZb
     Please record and enter it for verification.
     Verification:YLeLfkZb

     1 = telnet
     2 = SLIP
     3 = PPP

     Your choice:

kppp can be used to do that cumbersome task for you (eliminating the risk of losing that little sheet of paper that holds your current password at the same time). The key part of the following script is a combination of the Scan/Save keywords:

     Expect      Login:                     # wait for login prompt
     ID                                     # send ID
     Expect      Password:                  # wait for password prompt
     Password                               # send password
     Scan        is:                        # wait for '... next session is:' and
                                            # scan the preceding password
     Save        password                   # save the new password for next login
     Expect      Verification:              # wait for 'Verification:'
     Password                               # send new password
     Expect      choice:                    # wait for a prompt that let's you choose
                                            # between different options (telnet, SLIP, PPP)
     Send        3                          # choose option 3, i.e. PPP