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Cannot relay to external domains when using ISA Firewall 2000

Document ID: 10411

Synopsis

The following relay error is reported when trying to send to external domains. 'test@domain.com' on 11/13/2006 4:11 PM 501 5.7.1 This system is not configured to relay mail from <test2

More Information

Cannot relay to external domains when using ISA Firewall 2000 The following relay error is reported when trying to send to external domains. 'test@domain.com' on 11/13/2006 4:11 PM 501 5.7.1 This system is not configured to relay mail from to for

Diagnostic Steps

If you can send mail from the Web mail Client (i.e MailSite Express) but not any other clients then check that SMTP Authentication is enabled for ALL accounts within your mail client e.g. Outlook or Outlook Express.

To enable this in Outlook 2003:

  • Go to Tools > Email Accounts > View or Change Accounts > Select the account of interest
  • Go to More Settings > Outgoing Server > Enable 'My outgoing SMTP server requires Authentication'

If the problem continues, enable 'Protocol Exchanges' logging (found under Operation Log Flags) to file log. Attempt to send a message, wait for the error to return. Examine the logs to see if the client is send an 'Auth' command to the Mailserver.

If no commands are seen it could be that a firewall is not passing (or is blocking) the AUTH SMTP commands.

This has been an issue with the 'ISA Firewall 2000' for some customers. The default filters that are set up when you create the SMTP Server using the Server Publishing Wizard do not allow AUTH commands to pass through.

Firewall Resolution

Enter the AUTH command into the list of allowed SMTP commands. This is required if you want to allow external users to authenticate with an SMTP server published via an SMTP Server Publishing Rule. Users will not be able to authenticate with a SMTP server published via an SMTP Server Publishing Rule if the AUTH command is not added to the list and the SMTP filter is enabled.
To do this on the ISA Firewall:
  • Confirm that the 'Enable an SMTP command' check box is checked.
  • Type AUTH in the Command Name text box.
  • Type 1024 in the Maximum Length Bytes text box.
  • Click OK in the SMTP Command Rule dialog box.
    • The new command should appear in the list of SMTP commands on the SMTP Commands tab.
  • Click Apply and then click OK.
  • Close the ISA Server Management console.
  • Restart the ISA Server 2000 machine.
For other versions of ISA firewall, please refer to the product documentation for details on how to permit AUTH SMTP commands