Can't receive emails for users of restored server backups

OS type and version Ubuntu 22.04.2 LTS
Webmin version 2.021
Virtualmin version 7.5
Related packages Postfix

We recently setup a new UBUNTU 22.04.2 server hosting Webmin 2.021 & Virtualmin 7.5, with the aim of migrating off an existing Virtualmin server (Ubuntu 22.04.1, Webmin 2.013, VirtualMin 7.5) to this new server.

Once the setup was complete, we did a Full server backup of our existing VirtualMin servers and restored these to the new server.

When testing the new setup, we found that all incoming emails for restored accounts got rejected, with a message stating " Recipient address rejected: User unknown in virtual alias table
We then setup a new user account, which was able to receive and send without issues.

Digging deeper, we found that when setting up the new user, an additional Mail Alias was created, which had a \ inserted before the @part of the email address.
i.e user had an additional Mail Alias created called test\
This Mail Alias was not present for the restored user accounts.

If we add this Mail Alias to a restored user account, emails can then be sent and received without any problem. However, we have many hundreds of email accounts, so we don’t want to start adding aliases to every account unless its unavoidable.
Is there a standard setting we should change so that user accounts do not need this additional alias to receive postfix email?

Further, what is the default setup wrt mail aliases for Ubuntu?
Is the new server set up correctly (using Aliases) or is the old setup (without aliases) the default standard?
i.e we want to be able to restore server backups to a default “vanilla” VirtualMin server, with as little configuration changes as possible.

I think we have found the source of the problem.
On the old Virtualmin server, under virtualmin Advanced configuration, we had selected YES for
Create extra Unix user on Postfix systems when using user@domain format

This means that we have UNIX user accounts listed as and, which eliminated the need to create the MAIL Alias.

However, when we did the Server backup (using Neither Option to avoid impacting the automated incremental backups) and restored to the new server, the Advanced option for UNIX accounts was set to NO.
This means that the UNIX accounts were not imported and hence the Mail Alias is now required.

We will test importing with the switch set to Yes and see if the UNIX accounts are imported.
If not, we will either need to create them manually or create Mail Alias accounts.
(However, I am assuming that the default setting is NO, which means that it would be better to create the mail alias accounts now, so that any future restore is easier.)

Okay…this issue was confirmed in this BLOG.

1 Like

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.