I am having a problem emailing from one computer to another computer on the same network. I keep getting the error "config error: mail loops back to me (MX problem?)".

My situation is as such...

I have a split brain dns on a firewall for the internal network.

I am trying to email from one of the internal workstations to a sendmail server on the same internal network.

The ip address of the internal machine is 192.168.0.2 trying to email to 192.168.0.3 (sendmail server).

The address that I am trying to email resolves ok cause when I do a "dig mx <domain name>.com it comes up with 192.168.0.3 so why does it say the mail loops back to itself.

When I try to email root@192.168.0.3 it says that the host is unknown.

Any help would be greatly appreciated.

Probably because you have the workstation set as the final destination for user@yourdomain.tld. You need to make sure it's not configured to accept mail for final delivery.

The recipient of the mail is a user on the sendmail server.

On my sendmail server I am getting the error:

"did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA"

I have checked and all of my internal workstations have this problem except one which seems to work ok???

I forgot to mention that the workstations are linux boxes using sendmail to send mail locally.

I was reading here ( http://www.sendmail.org/faq/section4.html#4.5 ) and at the bottom it has a little blurb that says:

"Note: You can also get this error message (MX loops ...) when two sendmail systems talk to each other, and both have the same value of $j . The best solution is don't do that"

I know that the sendmail.cf file uses a $j to write to all these different places. How do I check the value of this $j variable so that I can see if they are different.

Also, now that this doesn't seem to be a networking problem, how do I move my thread to the software forum. I know that if I post somewhere else about something that is the same topic it is heavily frowned upon.

have you put the domain of the email address in /etc/mail/local-host-names

Thank you for your response rex.

Yes I did put the domain name in the local-hosts file. Have you ever heard or seen this error before?

as long as the domain is in /etc/mail/local-host-names
and your mx records are setup correctly

look for these lines in your /etc/mail/sendmail.cf file:

Cwlocalhost
# file containing names of hosts for which we receive email
Fw/etc/mail/local-host-names

# my official domain name
# ... define this only if sendmail cannot automatically determine your domain
#Dj$w.Foo.COM

make sure the Fw line is uncommented, if you have no luck with that uncomment the Dj line. replace $w.foo.com with your fqdn

May be this will help

http://www.linuxquestions.org/questi...y-etrn-823774/

You can see the values for $j $w, etc by issuing: sendmail -bt -d0.4
(that will put you in the sendmail program btw, to get out: /quit)
In my case, all the names for $j, $w, etc. were some varient of 'localhost' and not the hostname.domain.hld (the FQDN).
My problem was that the /etc/hosts file needed the FQDN in BOTH the 127.0.0.1 and ::1 lines as well as the line that has the IP hostname
Don't delete all the localhost localhost.localdomain entries, linux needs them too.
As soon as I changed the /etc/hosts file and did a 'service sendmail restart' things started working.