[Dovecot] Dovecot + SASL + allow_nets

[Marc Cuypers]

Hi,

When using dovecot for authentication of an SASL (postfix) request, i 
cannot use the allow_nets parameter.  The IP-address of the requester is 
not known in dovecot.

I would like to allow sasl for certain users, others are not allowed to 
access via SASL.
Some users can have access to imap and pop3 from certain IP-addresses.

How could i combine this in then dovecot configuration?

-- 
Best regards,

Marc