[50550] in North American Network Operators' Group
Re: Cisco fixup for SMTP (Mail Guard)
daemon@ATHENA.MIT.EDU (Stephen Sprunk)
Sun Aug 4 00:57:23 2002
From: "Stephen Sprunk" <ssprunk@cisco.com>
To: "Shaun Bryant" <sbryant@ThePit.org>, <nanog@merit.edu>
Date: Sat, 3 Aug 2002 23:47:53 -0500
Errors-To: owner-nanog-outgoing@merit.edu
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
