how to avoid spam mail from external network

[Paul Howarth]

On Thu, 2006-07-06 at 15:39 -0500, Aaron Konstam wrote:
> On Thu, 2006-07-06 at 16:35 +0100, Paul Howarth wrote:
> > Aaron Konstam wrote:
> > > On Thu, 2006-07-06 at 08:54 +0100, Paul Howarth wrote:
> > >> On Thu, 2006-07-06 at 11:15 +0530, yogesh at banasdairy.coop wrote:
> > >>> hi frieds
> > >>> i have mail server on linux
> > >>> my mail server generate spam mail
> > >>> how to avoid this spamming
> > >>>
> > >>> the spam mail will come from external globval network
> > >>> i thaught that my server any port is opren
> > >>> how to secure my mail server
> > >> You will need to tell people:
> > >>
> > >> * which mail server software you are running
> > >> * which configuration options you have changed from the defaults
> > >> * what the spam looks like (with full headers)
> > >>
> > >> Paul.
> > >   The above described information would be interesting but I think the
> > > answer is to use spamassassin which comes with the
> > > distribution. Instructions for use are on the web and in the file
> > > users_prefs.template. Use of procmail to separate the spam and non-spam
> > > streams would be useful.
> > 
> > He said his server was *generating* spam mail, which is a 
> > configuration/security/abuse issue.
> > 
> > SpamAssassin helps with filtering received mail, but not with this type 
> > of problem. Well, perhaps if SA was used for outbound mail too, but that 
> > would be partially addressing the symptoms rather than finding a cure.
> > 
> > Paul.
> > 
> You might be right but I read his whole message differently. In part of
> the message he says:
> >> the spam mail will come from external globval network
> > >>> i thaught that my server any port is opren
> 
> I think this is a difficulty with English problem. I can't quite see how
> his mail server could be generating the spam but I guess it is possible.

Could be that the server is an open relay, has an insecure PHP script
running on a web server on the same machine, many other routes. You're
right though, it's hard to tell unless the OP comes back and clarifies
things.

Paul.