Disabling PIX Mailguard on Cisco Firewalls

This article contains information on disabling the SMTP Fixup feature on Cisco PIX firewalls to resolve mail delivery issues caused by the Mailguard feature. It is intended for Administrators.

Cisco firewalls have a feature called SMTP Fixup. This is known to cause problems with mail delivery, and we recommend disabling it. See Broadcom's Tech Note: Cisco PIX Mailguard (SMTP fixup) Interoperability Issues article that covers the issues with PIX Mailguard (SMTP fixup):

To disable SMTP Fixup:

1. Establish a Telnet Session to log on to the Cisco PIX firewall. Alternatively, use the console to log on to the Cisco PIX firewall.
2. Enter the enable command.
3. Enter your Password when prompted.
4. Enter the following commands in sequence:

• • configure terminal
  • no fixup protocol smtp 25
  • write memory

5. Restart the Cisco PIX/ASA Firewall.