We discovered a problem on our machines running the Novell Client v4.91
sp3 ( which prevents communication with a Win2003 active
directory domain controller. Not only could the clients not join the AD
domain, they couldn't even map a drive to ipc$ on the DC, like this: net
use \\\ipc$ /user:Administrator mypassword

Running the above command yielded this error:
System error 5 has occured
Access is denied

Machines without the novell client did not have this problem. After hours
of troubleshooting and finally doing a packet trace, this appears to be
the problem:

During SMB negotiation between client and server, the client reported
that "EnableSecuritySignature" is disabled, causing the challenge/response
to fail. To fix the problem I changed this registry entry from a 0 to 1:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\lanmanworkstation\par

then restarted the Workstation service. After that, the client could
connect to the DC's ipc$, and could be added to the domain. However,
after the client was rebooted, the above registry entry magically changed
back to a zero, causing client-DC communication to again fail. So I
uninstalled the Novell Client, changed the registry entry back to 1,
rebooted, and the client was able to communicate again with the DC.

Is this a known issue? Please...there is no problem with communication
between client and server, ldap and dns are working, i can ping the
server, the username and password are correct...this is definitely a
Novell client problem.