Re: Open Proxy - how do I prevent it? (long mail)

From: Colonel Flagg (
Date: 04/04/03

From: (Colonel Flagg)
Date: Fri, 4 Apr 2003 16:30:08 -0500

In article <>,
> > At a guess, your smtp server is probably accepting mail from and to any
> >address on the net - i.e. it's probably acting as a relay usable by
> >spammers. Unless you have a good reason to be offering an SMTP service to
> >the world at large, you should probably block port 25; if OTOH you're
> >running your own MX there should be some way to configure qmail to only
> >accept mail destined for your domain.
> I am running my own MX, so blocking the port wouldn't help me much.
> I have tried setting up Qmail to only accept mail from local hosts,
> but I might have misconfigured something.
> Do you know any program or web page, that offers to test whether or
> not a site "offers" an open STMP relay?
> Regards,
> Thomas Rokamp

telnet to on port 25 from the IP address
associated with your mail server.

Colonel Flagg
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