Is this a firewall problem, perhaps?  Those packets translate to UDP
packets in bsd auth, and if there's some connection tracking going on,
it would probably reject a reply packet after 800+ seconds.

If that doesn't prove to be the case, take a look at a tcpdump of the
connection, to see whether the REP packet or its ACK is actually being
lost.

Dustin

-- 
Storage Software Engineer
http://www.zmanda.com