Environment
Novell NetWare 5.1
Novell NetWare 6.0
Novell NetWare 6.5
Novell NetWare 6.0
Novell NetWare 6.5
Microsoft Windows 2008 R2
Novell Client 2 for Windows 2008 R2
Situation
Connecting from a Windows 2008 R2 server to a NetWare server works fine. However, if the server doesn't access the mapped drive at least once every 60 minutes, the drive will go stale. It will not be accessible until someone logs out and back in on the Windows Server.
Resolution
Set NCP TCP KEEP ALIVE INTERVAL to something less than 60 minutes.
Cause
1) Network router/infrastructure device was set to kill connections that are idle (viz. no packets) for 60 minutes.
2) NCP TCP KEEP ALIVE INTERVAL was set to 89-90 minutes
Additional Information
The NCP TCP KEEP ALIVE INTERVAL is mean to address such cases. It's default setting is 9 minutes 32 seconds, which would have been sufficient to avoid this matter (in the scenario above). The job of this setting is to send a keep alive packet at the end of the interval. If no response is received, it then tears down the given IP connection.
As the interval was set larger than the router's setting, the keep alive packets were useless to maintain the session.
See TID 10013653 - How does Watch Dog occur with NetWare 5 Pure IP or SCMD Client? for further details.