[Dovecot] SOLVED Intermittent authentication failures

[Timo Sirainen]

On Fri, 2011-09-30 at 16:24 -0700, Eric Shubert wrote:
> >> CRAM-MD5 works sometimes:
> >> Sep 30 08:15:43 imap-login: Info: Login: user=<userA at domain.com>,
> >> method=CRAM-MD5, rip=192.168.252.8, lip=192.168.252.14, mpid=20301
> >>
> >> but (seemingly more frequently) the authentication fails:
> >> Sep 30 08:16:41 imap-login: Info: Aborted login (auth failed, 1
> >> attempts): user=<userA at domain.com>, method=CRAM-MD5, rip=192.168.252.8,
> >> lip=192.168.252.14
> >>
> My problem was indeed with the password caching. I changed
> cache_key=%u
> to
> cache_key=%u%r
> and that cleared things up.
> 
> I expect that this is only a problem when different client programs use 
> different login mechanisms, which was the case with this particular 
> group of users.

Auth mechanism shouldn't affect caching or vice versa. Maybe the %r just
happens to work around the real problem, which might still be there but
just less frequent.. Logs with auth_debug=yes could have been helpful in
figuring this out.