Well actually I found a line I had skipped over before it /etc/postfix/main.cf that had my old hostname. I changed it and that worked.
Now, I seem to be getting these messages now:
X-Spam-Checker-Version: SpamAssassin 3.2.1 (2007-05-02) on
X-Spam-Status: No, score=-0.0 required=5.0 tests=NO_RELAYS autolearn=ham
Received: by hostname.domain.net (Postfix)
id 923CC10FA04; Fri, 4 Apr 2008 16:33:35 -0400 (EDT)
Date: Fri, 4 Apr 2008 16:33:35 -0400 (EDT)
From: MAILER-DAEMON@hostname.domain.net (Mail Delivery System)
Subject: Undelivered Mail Returned to Sender
This is the mail system at host hostname.domain.net.
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The mail system
<firstname.lastname@example.org>: host smtp-server.columbus.rr.com[188.8.131.52] said:
553 hostname.domain.net does not exist (in reply to MAIL FROM
Is this happening because of reverse DNS issues?