First steps in Dovecot; IMAP not working

[Marnaud]

Le 14 oct. 2016 à 15:54, Aki Tuomi <aki.tuomi at dovecot.fi> a écrit:

> In your configuration, dovecot uses whatever user/group returned by PAM.

Excuse my ignorance, but what is PAM?

> Since the web user has never logged in, it has no directory under /var/mail.

Hmm… So it can’t log in because it has no directory and it has no directory as long as he does not log in, correct?

> If you want, you can 
> 
> a) override mail_uid and mail_gid in userdb/passdb
> b) pre-create /var/mail/webuser and chown it to webuser:ftpusers
> c) you can let ftpusers write to /var/mail.

Step b and c are ok for me, I believe.
I should override mail_uid and mail_gid to what?