NetWare OpenSSH: Rapid sequence of SCP sessions causes some sessions to fail

  • 7003232
  • 07-May-2009
  • 26-Apr-2012


Novell NetWare 6.5 Support Pack 7
Novell NetWare 6.5 Support Pack 6


If client systems are using SCP rapidly or simultaneously to transfer files to or from a NetWare server, some of the SCP transfers may fail.


Fixes have been made to the SCP threading design in efforts to correct this.  The fixes are present in NetWare 6.5 SP8.  Even with the update, if there is enough load placed on the server, it may still be possible to get this type of symptom.  However, the update improves the threading process which significantly reduces the chance of seeing this symptom.
For SP7 systems which administrators are not yet ready to update, the update can be pulled from the SP8 materials and applied individually.  Obtain the file /products/ssh/   from SP8.  It contains a SYSTEM folder with several NetWare NLMs.  Copy these NLMs into SYS:\SYSTEM.  Then reboot the system.
NOTE:  Instead of rebooting the system, you can UNLOAD SSHD and LOAD SSHD.  However, if sessions are active at the time you attempt to unload, a warning will occur along with a prompt of whether to unload or not.  If SSHD is unloaded while sessions are active, there is a chance the system could abend.  Fixes for this abend are also contained in the SP8 edition of SSH; however, as the SP7 edition is already loaded at this point, a risk still exists.

Additional Information

When the timing was just right, one SCP session being torn down could cause another SCP session to be closed prematurely as well.  With SP8, the timing of session closure has been modified to greatly narrow this window of vulnerability.  Some slight chance of failure still exists.  If this occurs, proper error codes are returned to the client.  Users or processes transferring files via SCP to or from a NetWare SSHD Server should retry in the event of failure.