Re: Cisco fixup for SMTP (Mail Guard)

["Stephen Sprunk" <ssprunk () cisco com>]

Thus spake "Shaun Bryant" <sbryant () ThePit org>
> I am currently working on a high volume mail project. The question came up
> whether or not the run Cisco's SMTP fixup protocol. I am looking for any
> experiences good or bad.

Last time I looked, the "mail guard" feature replaces EHLO messages with NOOP
(among other things).    Some ESMTP-capable mailers figure out what's going on
and retry with HELO, but others get confused and end up bouncing all mail going
through that path.

I don't know who decided EHLO is not a "safe" command, but (a) it's been
standard for many, many years, and (b) replacing it with NOOP does not have a
"safe" effect.  Do not use this feature if you value mail reliability.

> Please respond off list

Actually, this is far more on-topic than most NANOG drivel, so I'll respond here
:)

S