[CentOS] saslauthd for sendmail SMTP relay

Sun May 25 09:22:45 UTC 2008
Bernd Bartmann <bernd.bartmann at gmail.com>


I'm running a Centos 5.1 server that uses saslauthd to allow sendmail
SMTP relaying for some clients. saslauthd is configured to use method
"shadow" to lookup the username / password directly from /etc/shadow.
This setup has been working for several month now, but is broken since
last Monday. I haven't changed anything neither on the server nor on
the clients. Now whenever a client tries to relay email I see this
messages in the logs:

AUTH failure (LOGIN): authentication failure (-13) SASL(-13):
authentication failure: checkpass failed

saslauthd[3665]: do_auth         : auth failure: [user=username]
[service=smtp] [realm=] [mech=shadow] [reason=Unknown]

Does someone have an idea how to debug this further, esp. how to find
the real reason as the message [reason=Unknown] is not very helpful at

Thanks in advance,