Every 6 minutes ... broken pipe

[Andrew Tridgell]

The keepalives to the password server are essential because without
them the server will drop the idle connection. There is no way to
re-establish them due to the braindead design of SMB. The crypt-key
cannot be re-negotiated and is chosen by the server, so if any new
session setup calls come from clients after the password server
connection is gone then all you can do is fail them. That's bad.

Use security=domain (that solves the problem) or alternatively we
could keep a pipe open on the password server to keep it occupied.

Cheers, Tridge