Well the idea was not send email to a listserv that advertised I had an open relay and no idea how to close
it. That is a major security risk and urgent, IMO. Anyone using my server for bad things would likely create
a bad image for both my domain and the software, exim, that was being abused.
It turns out the problem was my running exim from inetd, which resulted in all hosts looking like they were
localhost. Yes I know it was probably in the manuals somewhere and did see a reference to something that, at
least to me, didn't make sense at the time.
Thank you everyone that posted answers.
Philip Hazel wrote:
> On Fri, 20 Jul 2001, hanasaki wrote:
>
> > should the following keep users from doing the following? If not....
> > what am I missing?
> >
> > exim.conf v3.22
> > ==========
> > local_domains = mydomain.com
> > #local_domains_include_host = true
> > local_domains_include_host_literals = true
> >
> > #relay_domains =
> > relay_domains_include_local_mx = false
> > headers_check_syntax
> >
> > host_auth_accept_relay = localhost
> > host_accept_relay = localhost
> >
> >
> > script
> > ==========
> > telnet mailsserver 25
> > helo blah
> > mail from:<spam@spam>
> > "RCPT TO:<a@???>
> > DATA
> > Subject: sub
> > info for you
> > .
> > QUIT
>
> This is probably the same situation as FAQ 0833, but since you haven't
> quoted the SMTP responses, I cannot be sure.
>
> For a host to be an open relay, it must do TWO things:
>
> (a) Accept mail for arbitrary addresses.
> (b) Deliver that mail to its intended addresses.
>
> Many people forget about (b).
>
> Possibly what you are missing is receiver_verify.
>
> --
> Philip Hazel University of Cambridge Computing Service,
> ph10@??? Cambridge, England. Phone: +44 1223 334714.
>
> --
> ## List details at http://www.exim.org/mailman/listinfo/exim-users Exim details at http://www.exim.org/ ##
