Symantec Email Gateway behind F5

Hi,

Since F5 load balance SMTP, the answer is still the same...

X-Forwarded-For header is only compatible with HTTP(S) protocol.

In SMTP, Received header (inserted by each SMTP relay) is in the header of Data and not in SMTP conversation. so you have to listen all SMTP conversation to catch start of DATA, then insert Received Header.

Until F5 doesn't create SMTP irule events, it will be difficult to do this... maybe you can be the one who will success :-)

The other solution is to define the BIGIP as default gateway.