Pesky virus

[Scot L. Harris]

On Fri, 2004-07-23 at 12:23, James Marcinek wrote:
> I'm no expert at this but I did some reading and was under the
> impression that people will use your mail server to send emails and
> that there's not a lot that can be done about it. I would definitely
> like to be proven wrong with this. The simply script something to
> telnet into your mail port and send emails... These emails are
> generated from your server so even setting your email to send only
> from your domain does not protect you. Is anyone listening that could
> shed some more light on this?
> 
> Thanks,
> 
> James

What you are describing is an email relay.  Most systems today ship with
relaying disabled (including all linux distros that I know of).  If you
have an open relay it will be found by the spammers and used.  This is
one reason to be very careful and sure of what you are doing when
modifying sendmail or one of the other MTAs available for linux.

If you have not modified your systems MTA configuration you should be
fine.

At work I see literally hundreds of attempts per day to relay email
through our mail server.  Each one of them is denied.

If you have any doubts about your servers setup do some reading on your
particular MTA.  You can also test this by simply telneting to port 25
of your server and issuing the following commands when you get a
connection:

helo testdomain.com
mail from: badspammer at spamu.net
rcpt to: hapless at victim.com
data
this is test data