confusing authentication

[Marten Lehmann]

Hello,

I'm using getpwent for admin authentication and salsdb for commoon 
mailbox users. I noticed a strange behaviour:

I'm not using salsauthd. But when I'm just writing

sasl_pwcheck_method: getpwent auxprop

I always get

NO Login failed: user not found
(only admin users not found)

When I have

sasl_pwcheck_method: getpwent auxprop saslauthd

and salsauthd isn't running I get

NO Login failed: generic failure

Why do I have to include salsauthd and even need to have it running, 
while it is not being used?

Regards
Marten