Error: "System error 240 has occurred. The session was cancelled"

  • 10080030N
  • NOVL86841
  • 07-Feb-2003
  • 14-Nov-2003

Archived Content: This information is no longer maintained and is provided 'as is' for your convenience.

Fact

Novell NetWare 5.1

Novell NetWare 6.0

Novell Native File Access Pack

Novell Native File Access Protocols

Novell Native File Access for Windows

Symptom

Error: "System error 240 has occurred. The session was cancelled"

Error: "System error 64 has occurred. The specified network name is no longer available."

Error: "System error 1351 has occurred. Configuration information could not be read from the domain controller, either because the machine is unavailable, or access has been denied."

Error: "Systemfehler 240. Die Sitzung wurde abgebrochen"

The NET USE command returns "System error 240 has occurred. The session was cancelled" after 2 minutes, when trying to connect to a Native File Access for Windows CIFS server.

Cause

The NetWare CIFS server suddenly stops responding to incoming SMB_COM_NEGOTIATE requests. Normally, the NetWare CIFS server would respond with a selection of the latest CIFS Protocol Dialect "NT LM 0.12". A LAN trace would show that the NetWare TCP/IP stack acknowledges the income of the client's SMB_COM_NEGOTIATE request, but the NetWare CIFS server does not return a response. After waiting for a response from the NetWare CIFS server for about 2 minutes, the client will time out and return the error message "System error 240 has occurred. The session was cancelled" to the user.

When you have configured Native File Access for Windows to handle authentication in domain mode, the NetWare CIFS server stops responding to incoming SMB_COM_NEGOTIATE requests, if it cannot (re)connect to the Primary Domain Controller (PDC).

Fix

Section "2.6.3 Connection Management" of the expired CIFS specification draft-leach-cifs-v1-spec-02 reads: "a server may terminate the transport connection when the client has no open resources on the server, however, we recommend that the termination be performed only after some time has passed or if resources are scarce on the server".

If the Primary Domain Controller runs on a Windows NT or Windows 2000 server, the PDC will by default terminate the connection with the NetWare CIFS server in about 15 minutes, since the NetWare CIFS server only uses the connection with the PDC for user authentication and has no open resources on the PDC. Once the connection is terminated, the NetWare CIFS server will try to reconnect. Older versions of the NetWare CIFS server seemed to stop retrying if they could not reconnect to the PDC for a while. Restarting the Native File Access for Windows would force the NetWare CIFS server to retry establishing a connection with the PDC again. At the System Console prompt of the NetWare server running Native File Access for Windows, you can run CIFSSTOP.NCF and then CIFSSTRT.NCF to restart Native File Access for Windows. This problem does not seem to occur anymore with CIFS.NLM version 1.30 of September 3, 2003 and later.

If you have configured the NetWare CIFS server to handle authentication in domain mode, then please ensure that you have specified both, the name and the IP address of the Primary Domain Controller.

If the Primary Domain Controller runs on a multi-homed Windows NT or Windows 2000 server, the NetWare CIFS server should be able to reach each IP address of the multi-homed server at UDP port 137 and TCP port 137 and 139, even though you can configure only one IP address with the CIFS configuration. This requirement is due to a defect with the NetWare CIFS server, which is reported to Novell engineering.

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