AOL blocking MailScanner messages!

[Jeff A. Earickson]

Y'all,
   I ran Rickert's sendmail ruleset for about 6 hours yesterday, then
removed it and looked at the 500 sendmail rejects that it generated
for the "Fix reverse DNS" error.  I rejected emails from 364 unique
IP numbers.  I wrote a script to do a whois on these numbers and the
info was ugly.  Yes I was rejecting probable spam from APNIC, but I
also zapped a lot of stuff from other universities, McGraw-Hill books
and other publishers, Amazon (the original spammers!), IBM, the FAA (!),
etc.  I expect to hear some screaming about my experiment.

While I think this is a great idea in theory, in practice it does a
lot of collateral damage.  I'll let AOL reform the world before
trying it again.  They will have to convince AT&T (for one) to change
their DNS for their subblocks.

--- Jeff Earickson
    Colby College

On Thu, 4 Dec 2003, Mike Kercher wrote:

> Date: Thu, 4 Dec 2003 18:37:34 -0600
> From: Mike Kercher <mike at CAMAROSS.NET>
> Reply-To: MailScanner mailing list <MAILSCANNER at JISCMAIL.AC.UK>
> To: MAILSCANNER at JISCMAIL.AC.UK
> Subject: Re: AOL blocking MailScanner messages!
>
> I'm running it and I love it.  For the most part, legit email has legit DNS.
> If not, admins on the other end need to get off their ass and make their
> networking correct, complete and in compliance with the RFC's.
>
> Mike
>
>
> > -----Original Message-----
> > From: MailScanner mailing list
> > [mailto:MAILSCANNER at JISCMAIL.AC.UK] On Behalf Of Jeff A. Earickson
> > Sent: Thursday, December 04, 2003 11:16 AM
> > To: MAILSCANNER at JISCMAIL.AC.UK
> > Subject: Re: AOL blocking MailScanner messages!
> >
> > >
> > > However, this has nothing to do with RDNS at all, and nothing to do
> > > with what AOL is doing. AOL is implementing refusal of mail from
> > > servers that do not have a reverse DNS lookup for their IP.
> > It's not
> > > rocket science to do in sendmail, i.e. something like this:
> > >
> > > http://www.cs.niu.edu/~rickert/cf/hack/require_rdns.m4
> > >
> >
> > Does anybody else out there run this hack, or something
> > similar for Exim/ Postfix?  I'm giving it a test run on my
> > mail server right now, and I wonder if I am shooting myself
> > in the foot.  Virtually all of the rejections I see smell
> > spammy to me.  Comments?
> >
> > Jeff Earickson
> > Colby College
> >
>