Ignoring unqualified MX's ?

torben fjerdingstad unitfj-bind at tfj.rnd.uni-c.dk
Thu Mar 23 10:41:25 UTC 2000

On Wed, Mar 22, 2000 at 06:25:59PM +0000, Barry Margolin wrote:

> >> >>One of our customers has had a lot of mail loops because
> >> >>a spammer has this in his return-path:
> >> >>Return-path: info at internet.net
> >> >>
> >> >>The problem with that is:
> >> >>
> >> >>$ host -t mx internet.net
> >> >>internet.net            MX      5 localhost
> >> >>
> >> >>Is it possible to make bind discard that information without
> >> >>creating a local master zone file for the bogus zone?

> >I use qmail, the mentioned customer is using PMDF (as far I remember).
> I'm not sure why that MX record is causing you problems, anyway.  It points
> to the name localhost in the root domain, but there is no such name.  Why
> is your mailer trying to send it to localhost.yourdomain?

Actually, it was not my mailer. It tries to send the bounces to
localhost., which usually is at ip
My mailer (qmail) does the same. And sendmail does.

I tried to send mail to nosuchuser at internet.net from
qmail and sendmail. Both try to deliver to localhost.

> Your subject line refers to "unqualified" names, but the DNS protocol
> doesn't actually have such a thing.

You are right. localhost. is a fully qualified toplevel domain

Anyway, I believe email addresses like tfj at dk, tfj at net and
other toplevel email adresses are illegal.

If that is correct, it is sane to discard MX and A records
pointing to a toplevel domain. The well known toplevel
domains neither have A or MX records.

> Barry Margolin, barmar at bbnplanet.com
> GTE Internetworking, Powered by BBN, Burlington, MA
> *** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.

I respect that, and reply to the bind-users list.

Med venlig hilsen / Regards 
Netdriftgruppen / Network Management Group

Tlf./Phone   +45 35 87 89 41        Mail:  UNI-C                                
Fax.         +45 35 87 89 90               Bygning 304
E-mail: torben.fjerdingstad at uni-c.dk       DK-2800 Lyngby

More information about the bind-users mailing list