Question : Linux (Fedora Core 7) >Apache > Sendmail > Exchange 2k7

I'm trying to get sendmail to forward to an internal mail server behind a firewall (both exchange and sendmail are behind the firewall, same network). The perl script sends to external address just fine, however, when trying to send to the internal mail server, I get the following bounced mail error codes:

Remote-MTA: DNS; [127.0.0.1]
Diagnostic-Code: SMTP; 550 5.1.1 ... User unknown

I have mX records pointed at my mail server internally, but the e-mail keeps bouncing as if it thinks the Linux server is ubifcu.com

I do have my exchange server setup as the smarthost in sendmail.cf, and I can create an SMTP session via telnet.

Can anyone shed some light on this?

Answer : Linux (Fedora Core 7) >Apache > Sendmail > Exchange 2k7

What domain names is your linux box serving? Do you forward just some mail addresses of a single domain?

Is ubifcu.com in your /etc/mail/local-domain-names file? If it is try to remove it.

If all addresses of a domain should be forwarded, you can write in your /etc/mail/mailertable:
ubifcu.com smtp:[192.168.0.10]

Where 192.168.0.10 is your exchange machine IP.

Do not forget to run make in /etc/mail after making changes there