Cisco fixup for SMTP (Mail Guard)
Stephen Sprunk
ssprunk at cisco.com
Sun Aug 4 04:47:53 UTC 2002
Thus spake "Shaun Bryant" <sbryant at 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
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