I have changed over when it became available to the username format username@domain in postfix.
That has created a few problems for the users already setup with the old style.
Under the admin interface I cannot read that users email and for the user, whilst they can log in through squirrelmail, it does not display their mailboxes.
Regular pop3/imap access works fine.
Hey Dan,
Yes, there are still many issues with @ in usernames, and we’re working on them. I don’t recommend use of this format at this time (though I should be much more emphatic about that in the documentation and FAQ). Postfix just flat out refuses to work with @ in usernames (due to some good reasons which Wietse has discussed on the mailing list) and so we have to work around that issue by creating two users for each mailbox. One for delivery (with no @) and one for pickup (with an @). In other words, it’s a clever (but nasty) hack to deal with two very strongly held but opposing opinions: Wietse’s opinion that no username should have @ in it, and web hosting providers opinion that usernames must have @ in them. If you must use @ in the username, switching to sendmail may be the best advice I can give you (Sendmail is also well supported by Virtualmin). We’ll get it all worked out with Postfix eventually…but everytime we whack one bug another one comes along.
But, in your case, it sounds like the old users don’t have the second username in /etc/passwd. Probably actually simple to fix. Unless I misunderstand the symptoms.
Is it safe to just flip over to using sendmail from postfix with the existing users/domains in place?
I found a brief solution to both.
[BR]1) I went into /etc/postfix/virtual and changed the line for the user in question which was:
charo@domain.com charo.domain
to
charo@domain.com charo.domain[font color=red].com[/reftxt]
I saved the file and restarted postfix.
Mailbox showed as 0K of mail (oh crap!)
So I changed it back to the original:
charo@domain.com charo.domain
Saved and restarted postfix
Great! Now I can read user mail again for that user!!
Hey Dan,
While it is “safe” it isn’t a “just flip” process, I’m afraid. There is the virtual->virtusers table conversion that has to happen, and I don’t believe there is any automatic way to accomplish that. I just replied to a query about the opposite conversion here:
http://www.virtualmin.com/forums/message-view?message_id=50612
Once I have examples of both types of file, I’ll be making a little perl script to do either conversion automatically.
The aliases files are probably fine, though you’ll probably want to clean up the extra usernames (the ones without @ in them). There are probably one or two other things to keep in mind, though I’m so unfamiliar with Sendmail that it’s hard for me to predict exactly what.
Hey Dan,
Excellent. Good to know that it’s not impossible to get it all working. 
I think we’re pretty close to having it work in most situations, but changing when users already exist is definitely a likely source of trouble. We’ll need to come up with some better checks and convertors for such circumstances.