Configure dovecot and exim4 to accept username#company.com logins - authentication

Question

I can login on my IMAP server using my username, but can't using username#company.com (related: Dovecot Authentication failed if trying login with #domain) . Same thing happens for SMTP with exim4.
How can I setup dovecot (IMAP) and exim4 (SMTP) to allow username#company.com as the login?
EDIT: I'm using driver = passwd for the userdb, and driver = pam for the passdb.

Answer 1

I had the same question, and similar reasons. This may not be the best wa but I used a test account, lets call it 'user' for the sake of illustration and, copied the user's line in /etc/passwd (I'm on a Ubuntu cloud server), and changed the name on the copied line-- just adding the fqdn so the user UID has two names: 'user#mydomain.com' and the original, just 'user'. I setup the account first on Thunderbird with just 'user' to login to dovecot and exim, tested send/recieve ok. Then changed the login on Thunderbird for both servers to 'user#mydomain.com'. I had to re-enter the password, but it appears to have worked spectacularly well. It tested send/recieve ok, and otherwise appears the same as before. Now, I'm short on time so I set the password separately for both accounts, but I'm not sure that part is necessary. I'll have to check later, but I think pam looks up passwords matched to the PID (if I'm wrong about that, please someone tell me!). Anyway, more testing later. I'll let you know if there are deleterious side-effects. Aside: it may be possible to simply add the full email address as an alias in /etc/alias but I haven't tested that, and I just thought of it. Anyone try that one, leave a comment! Thanks! Ciao...

Answer 2

You have to create users in complete form of user#domain.tld.
Setup login autocompletion by #hostname if domain part is omitted, before dovecot-auth invocation.
As far as there is lot of dovecot/exim howtos, there is no ready-to-use recipe for your case.

Answer 3

You can change your SQL query to use only the first part before the # sign by using the substring_index() function. Conveniently, this string search query will return the whole string if there is no # sign. This means that if the customer enters "user#domain.com", it will use the correct value (just the "local_part"), and if the customer enters just "user", it will return the whole string.
Example:
mysql> select substring_index('user#example.net','#',1);
+-------------------------------------------+
| substring_index('user#example.net','#',1) |
+-------------------------------------------+
| user |
+-------------------------------------------+
1 row in set (0.00 sec)
mysql> select substring_index('user','#',1);
+-------------------------------+
| substring_index('user','#',1) |
+-------------------------------+
| user |
+-------------------------------+
1 row in set (0.00 sec)