I created a new virtualmin server on Ubuntu 8.04 a few days ago, moving all my users to it from cPanel.
I've been really happy with it until now. While trying to solve the external mail client authentication nightmare (which was a success, damn saslauthd!), I've run in to an issue.
Earlier today I changed the hostname in the Postfix configuration, and now ALL mail is coming back bounced, with the following message:
Aug 18 15:22:13 kolacja postfix/error: 1AD121D2728: to=<:blackhole:@mydomain.net>, orig_to=<firstname.lastname@example.org>, relay=none, delay=0.24, delays=0.23/0/0/0.01, dsn=5.0.0, status=bounced (User unknown in virtual alias table)
Basically, ANY emails sent to users on the system get a bounce message as above showing in /var/log/mail.log. The end user receives the bounce message below.
Is there anything I can do to fix this, and quickly?
All I changed was adding the server's IP in to /etc/resolv.conf (it didn't seem to be there, but 127.0.0.1 was), and changing 'myhostname' in /etc/postfix/main.cf.
This is the mail system at host server.mydomain.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
<":blackhole:"@mydomain.net> (expanded from <email@example.com>): User unknown
in virtual alias table
Reporting-MTA: dns; server.mydomain.net
X-Postfix-Sender: rfc822; firstname.lastname@example.org
Arrival-Date: Tue, 18 Aug 2009 15:07:51 +0100 (BST)
Final-Recipient: rfc822; ":blackhole:"@mydomain.net
Diagnostic-Code: X-Postfix; User unknown in virtual alias table