On 3/18/07, Sid Carter <[EMAIL PROTECTED]> wrote:
Hi,
I am currently running OpenBSD 4.0 as a greylisting server. We have
found that many Microsoft Mail Servers/Mail Marshal cannot get past the
greylisting. On further investigation, we found out that the MS Mail
servers send a NOOP before they start sending other SMTP commands and
spamd returns a 451 even for a NOOP causing the SMTP connection to
terminate and the connecting mail server doesn't even get greylisted,
since it hasn't even sent a "MAIL FROM" and "RCPT TO".
I've seen no mention of this in the archives, so was wondering if this
is intended and if there is a permanent fix for this.
We've temporarily patched spamd.c, so that spamd does nothing on a NOOP
command as required by the SMTP RFC and we've seen that the MS Mail
servers get properly greylisted and subsequently whitelisted.
Might be useful if you would include details, and lots of them, on a
subject like this. "MS Mail Servers" is generic and meaningless; is it
Exchange? Is it the SMTP Server? Something else? What software
version(s)? OSes and versions?
More than anything, packet captures illustrating the behavior would be
useful too.
DS
