Maybe it was, maybe it was not. I was surprise too.
But it is what it showed. The welcome signature said Microsoft ESMTP
Server and the vendor I was dealing with at the time, when we saw it,
confirmed it was their MS SMTP server. I did't bother to ask about PROXY
setups, etc, or go into why it happen because it wasn't the purpose of
Sure, I was surprise by it too. But even if was a AVS related proxy,
it was still a violation, proxy or not :-)
So I merely focused on the semantics currently in the specs - it didn't
ignore the string nor the NOOP command itself.
If the clarification "nit" is not deem worthy of anyone's time, then
Hector Santos, CTO
At 14:39 28-11-2007, Hector Santos wrote:
I just came across a transaction where a Microsoft ESMTP server
rejected it with a 421 response.
Are you sure it's a Microsoft ESTMP server and not some application
proxy filtering SMTP commands?