Spam sent to me from my own mail server ?
m.seaman at infracaninophile.co.uk
Wed Aug 27 17:41:34 UTC 2008
Peter Ulrich Kruppa wrote:
> Steve Bertrand schrieb:
>> Peter Ulrich Kruppa wrote:
>>> for some time now I keep receiving spam mails from my own (small)
>>> mail server, some of them with faked usernames some of them even with
>>> my own (ulrich at ...).
>> The only way to tell for certain is to review the headers of the message.
> Received: from 18971066005.user.veloxzone.com.br
> .br [184.108.40.206] (may be forged))
> by pukruppa.net (8.14.2/8.14.2) with SMTP id m7RGmXTN038419
> for <ulrich at pukruppa.net>; Wed, 27 Aug 2008 18:48:34 +0200 (CEST)
> (envelope-from ixd at pukruppa.net)
It's a simple forgery by the spammer. They just claim to be sending from
your domain because there are apparently people that run internet connected
mail systems where doing that makes it easier to inject spam... Either
that, or the spammers figure they'll get you with the bounce-o-gramme even
if the first delivery doesn't work.
There are a number of measures you can take against such things. One thing
that is pretty easy to implement is to set up SPF records in the DNS. This
won't stop the spammers attacking you this way, but it does mean that
spamassassin will award them lots of spam points and probably reject the
If you're using sendmail as your MTA, then look at implementing the
following features in your $(hostname).mc:
FEATURE(greet_pause, `5000')dnl ## 5 seconds
These are pretty cheap resource wise and block many of the most egregious
spammers. There's a lot more you can do than that in setting up sendmail
to be spam-resistent -- much more than I can describe in an e-mail like
Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard
PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate
Kent, CT11 9PW
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