Any chance of blocking these?

Scott Silva ssilva at
Mon Jun 8 21:46:35 IST 2009

on 6-6-2009 1:52 PM Ljósnet spake the following:
> Hello, I have a small problem with few MS Exchange servers who are
> infected with some kind of virus/trojan. They are sending mail through
> my gateway which is fine, but I need to be able to stop them from
> sending mail which dont have any valid address in from=< > field until
> I get the system administrator to clean their server.
> In the maillog it looks like this:
> sendmail[12542]: n56Ki9EY012542: from=<>, size=23860, class=0,
> nrcpts=1, msgid=<fiplj8nhX00000e8f at>, proto=ESMTP,
> daemon=MTA, relay=[]
> Is it possible to somehow stop servers/clients from being able to send
> through my gateway when there is no valid from= address?
> Thanks!
Since you gateway for them, do you do any recipient verification? Do they?

This could be normal bounce messages from unknown recipients if your system is
passing them on unstopped. They might have whitelisted your gateway thinking
you would be stopping this stuff.

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