After introducing a brand new spanky Cisco ASA 5505 into our live production envoirnment to protect our servers from the baddies, a weird occurrence began. E-mails were being stored in the Q within IIS’s internal SMTP engine.

Hours and hours of debugging and testing every possible stage of e-mails took me to the point of suicide. Looking through the logs at the emails sending, the HELO, MAIL FROM and RCPT TO were all happening fine. The problem occurred at the DATA segment.

It turns out, even in previous Cisco PIXs, the inspection aspect of the ASA tears the DATA segment apart for inspection. 8 hours later, ‘inspect esmtp’ was turned off.

I sat back, watched 500+ mails fly out and wondered how I would die my hair back to it’s original colour.