[Samba] Can't log in new users

[Thomas Riedrich]

We have Samba 3.0.9 on SuSE acting as a PDC for our Windows clients 
(mainly XP, some 2k). We have the problem that sometimes newly created 
users can't log in, Windows says that the domain is not available. We 
checked all network settings on the client machines, and everythings 
fine, for our existing users also everything is okay. When I create a 
new user on the Samba server and try to log in, then I get the "domain 
not available" message again. A strange thing is that "net view 
server_name" on one of the clients very often says that the server has 
reached it's maximum connections, although we didn't specify a max 
connection limit. When a login attempt fails, there's no error at all in 
the Samba logs or in the Windows event log. When I just try to log in 
the new user again and again, then it sometimes suddenly works 
perfectly, and once it works it never fails again.

Any ideas what could be the problem? If you need more info, please tell me!

Thanks,
Tom