After user has been successfully authenticated, Dovecot looks up the user's userdb information. The userdb lookup is also done by [:LDA:deliver] to find out how to deliver mails for the user.
The user database lookup returns:
User's [:UserIds#mailusers:UID] (UNIX user ID)
User's [:UserIds#gids:GID] (UNIX group ID)
[:MailLocation:Mail location] (if needed to override the default mail_location setting)
Optional [:UserDatabase/ExtraFields:extra fields] which are sent to the IMAP/POP3 process in environment variables.
The user and [:PasswordDatabase:password databases] may be same or they may be different depending on your needs. You can also have [:Authentication/MultipleDatabases:multiple databases].
Currently supported user databases are:
[wiki:AuthDatabase/Passwd Passwd]: System users (NSS, /etc/passwd, or similiar)
[wiki:AuthDatabase/PasswdFile Passwd-file]: /etc/passwd-like file in specified location
- [wiki:AuthDatabase/LDAP LDAP]: Lightweight Directory Access Protocol
- [wiki:AuthDatabase/SQL SQL]: SQL database (PostgreSQL, MySQL, SQLite)
- [wiki:UserDatabase/Static Static]: Userdb information generated from a given template
- [wiki:AuthDatabase/VPopMail VPopMail]: External software used to handle virtual domains
- [wiki:UserDatabase/Prefetch Prefetch]: This assumes that the passdb already returned also all the required user database information