XFOR: IMS/IMC Will not Dial an ISP as Specified (175410)

SYMPTOMS

The Microsoft Exchange Server version 5.0 Internet Mail Service (IMS) and the Microsoft Exchange Server version 4.0 Internet Mail Connector (IMC) may stop periodically when dialing an Internet Service Provider (ISP).

The dial-up schedule is specified in the Dial-up Connections property page in the Microsoft Exchange Administrator program.

MORE INFORMATION

Many ISP's require some sort of user input after the initial modem connection has been established. Typically this is to select the service type (for example, PPP) and to enter the user account details, in other words, the username and password. Because this input needs to be automated for the IMS or IMC to connect and send or receive mail, a 'post-connect' script is used. This script is usually supplied by the ISP, but it is also possible for you to write your own. Please refer to the script.doc in the \winnt\system32\ras directory on your Windows NT Server for further information on writing these scripts.

Occasionally, the ISP may not respond to the 'post-connect' script and eventually the IMS or IMC will disconnect from the ISP leaving the script processor running. This causes the Remote Access Service (RAS) port to remain locked open, preventing any further connections. The IMS or IMC will appear to not make any further attempts to dial the ISP. Stopping and starting the IMS or IMC will cause the following event to be logged in the Windows NT Application Log on each attempt to dial the ISP:

   Event ID: 4106
   Source: MSExchangeIMC
   Category: SMTP Interface Events

   The dial-up connection 'OzEmail' could not be made. The error reported
   was: [633] The port is already in use or is not configured for Remote
   Access dial out.

Rebooting the Windows NT Server will free the locked RAS port.

RESOLUTION

To avoid this situation, a script will need to be written or modified that has specific timeout parameters for each 'waitfor' command. The success of each 'waitfor' command should also be tested before the script proceeds to the next command. If the situation arises where the ISP does not respond to the script, the script will stop processing after the timeout has been reached and when the IMS or IMC disconnects, the RAS port will not remain locked thus allowing the IMS or IMC to redial as scheduled.

Here is a sample script with the additional timeout logic added. Please note that this script is specific to the OzEmail ISP in Australia and may not work with any other ISP. Please contact your ISP for further information as to the script requirements.

  ; OzEmail Script for PPP Access
  ;
  ; Last revised: October 10 1997

  ; Main entry point to script

  proc main

     waitfor "ervice?" until 90
     if $SUCCESS then   ;  Checking whether this is successful...
     transmit "p^M"

     waitfor "sername:" until 60
     if $SUCCESS then   ;  Checking whether this is successful...
     transmit $USERID, raw
     transmit "^M"

     waitfor "assword:" until 60
     if $SUCCESS then   ;  Checking whether this is successful...
     transmit $PASSWORD, raw
     transmit "^M"

     endif
     endif
     endif

  endproc