[Dovecot] SASL from remote server

Is there a way, using Dovecot and Postfix, to use SASL from a remote server? Since it appears the communication uses Unix sockets, does this mean it is restricted to local services only?

I have a two-server configuration, where my firewall also runs the mail gateway/filter (Postfix + ASSP). My internal server has Postfix + Dovecot. Right now I have my internal server configured to use Dovecot SASL, but the external server is still using the Courier authdaemon against the LDAP database.

-- Daniel