We are currently are running mailman on a Redhat box called listserv. This box sits in the DMZ. We also have our mail servers which are sitting inside the DMZ which pass traffic to our sendmail relay box to get to "listserv". Our mail is current mail setup looks like this:

Groupwise --------> Sendmail Relay ----------> Listserv (Client mails to list) (Relays mail to DMZ) (Accepts list and mails out)

Once listserv gets the mail it then delivers to the recipients. It's route is like this:

Listserv ----------->Sendmail Relay------------>Recipients (Can be internal or external)

On the Sendmail Relay I see mail successfully going from Groupwise to Relay to Listserv. They are all accepted and reach the correct place. But when Listserv sends the mail back out to the recipients I see the following errors on the Relay server from the maillog:

Listserv maillog:

stat=Deferred: Connection timed out with sendmailrelay.xxxxx.xxxx

Sendmail Relay maillog:

May 23 14:07:31 hostname sendmail[19397]: l4NJ1qpd019397: listserv.xxxx.xxxx [xxx.xxx.xxx.xxx] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA

May 23 14:14:32 hostname sendmail[19439]: l4NJEUUY019439: lost input channel from xxxx.xxxx.xxxx [xxx.xxx.xx.xxx] to MTA after mail

I have replaced the hostnames and ip addresses with xx for security reasons. The mail successfully makes it from the user through the relay and then to the listserv. But when it comes bash through, it get the errors.

I can telnet to the sendmail relay on port 25 from listserv just fine, I can send and external mail to my earthlink account from listserv just fine using the command line "mail -s Test xxxxx@earthlink.net. I can see my mail successfully go through the listserv and the mail relay, then out. But when it tries to send outbound to a list is when it doesn't go through and I see the message.

Any help would be appreciated. Thanks.