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

(Last modified: 14Jul2004)

This document (10092786) is provided subject to the disclaimer at the end of this document.

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 (CIFS)

symptom

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

Domain authentication fails when Primary Domain Controller and NetWare CIFS server are in different subnets.

cause

On the NetWare CIFS server, the Authentication Mode was set to 'domain'.
The Domain name and WINS address were configured.
No Primary Domain Controller details were configured and hence the CIFS server should resolve the name and IP address of the PDC per WINS.

A LAN trace showed that on startup, the NetWare CIFS server sent a request to the NetBIOS name service (UDP port 137) at the configured WINS server in order to resolve Domain Controllers for the configured Domain. The WINS server answered with the IP addresses of Domain Controllers for the given Domain. Next, the NetWare server wanted to send a NETLOGON query for Primary Domain Controller to the NetBIOS datagram service (UDP port 138) at the first resolved Domain Controller's IP address. However it sent the NetBIOS datagram to the reversed IP address instead and hence, the NETLOGON query for Primary Domain Controller never arrived at the resolved Domain Controller for the given Domain.

At this point, one of the following problems can occur:
- The reversed IP address is not reachable. In such case, a router would return an ICMP message of type 3 (Destination Unreachable), code 0 (Net Unreachable) or 1 (Host Unreachable) or type 11 (Time Exceeded), code 0 (Time To Live Exceeded In Transit).
- The host at the reverse IP address does not run the NetBIOS Datagram Service. In such case, the host at the reverse IP address would return an ICMP message of type 3 (Destination Unrachable), code 3 (Port Unreachable).
- The host at the reverse IP address runs the NetBIOS Datagram Service, but is not a PDC for the configured Domain. In such case, the host at the reverse IP address will simply discard the NETLOGON query from the NetWare CIFS server.

If any of the above three errors occur, the The NetWare CIFS server won't get a reply to its NETLOGON query for a Primary Domain Controller of the given Domain, which it unicasted to the reversed IP address. The NetWare CIFS server will time out in about two seconds, and then broadcast the NETLOGON query for a Primary Domain Controller of the configured Domain. If no PDC for the configured Domain exists in the broadcast domain, the NetWare CIFS server will not be able to resolve the PDC nor establish a connection for passthru domain authentication. As a consequence, the Client for Microsoft Networks will return the message "System error 240 has occurred. The session was cancelled" to the user, when he/she tries to connect to the NetWare CIFS server with the NET USE command.

fix

This defect is fixed with the field test CIFS.NLM version 1.50 of June 9, 2004 (size 359,172 bytes) or later. You can obtain this field test version with Novell Technical Services.

Work-around: Configure the host name and IP address of the Primary Domain Controller for the configured domain in Console One the following way:
1) Right-click the Server object of the NetWare server running Native File Access for Windows and select 'Properties...'.
2) Select the 'CIFS' > 'Config' tab.
3) Enter the 'Name' and 'Address' of the 'Primary Domain Controller' and click 'OK' to save your changes to the Server object.
4) At the System Console prompt of the concerning NetWare server, enter 'CIFSSTOP' and then 'CIFSSTRT' to make the NetWare CIFS server learn the configuration changes.

document

Document Title:	Error "System error 240 has occurred. The session was cancelled"
Document ID:	10092786
Solution ID:	NOVL96861
Creation Date:	10May2004
Modified Date:	14Jul2004
Novell Product Class:	Connectivity Products

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