Samba smb_lookup -104 and -5 errors

Had an otherwise stable Samba domain member server stop authenticating
clients today. /var/log/messages revealed

Nov 12 10:19:15 hostname kernel: smb_trans2_request: result=-104,
setting invalid
Nov 12 10:19:45 hostname kernel: smb_lookup: find //request failed,
error=-104
Nov 12 10:20:15 hostname kernel: smb_lookup: find //request failed,
error=-5
Nov 12 10:20:45 hostname kernel: smb_lookup: find //request failed,
error=-5
Nov 12 10:21:16 hostname kernel: smb_lookup: find //reply failed,
error=-5

Turns out the WINS server specified in smb.conf was down. Specifying a
different WINS server and restarting the Samba daemons solved the
problem.

Just committing this to the archives in case anybody else ever has
this problem...