Mailguard
Problem
Can't send or receive some messages through a Cisco ASA firewall.
Solution
Turn off Mailguard on the ASA:
ASA# conf t
ASA(config)# no fixup protocol smtp 25
ASA(config)# exit
ASA# write me
Building configuration...
It may be necessary to reset/reload the ASA after making this change.
Discussion
Dammit, Cisco.
To determine whether Mailguard is running on your Cisco PIX or Cisco ASA firewall, Telnet to the IP address of the MX record, and then verify whether the response looks similar to the following:
220*******************************************************0*2******0***********************
2002*******2***0*00
Old versions of PIX or ASA:
220 SMTP/cmap_____________________________________ ****read
For more information, visit the following Cisco Web sites: