Groupwise server stops communicating and runs out of packet receive buffers.

  • 7008924
  • 30-Jun-2011
  • 09-Dec-2013


Novell GroupWise 8 Support Pack 2
Novell GroupWise 8 Support Pack 3
Novell NetWare 6.5 Support Pack 8
Novell GroupWise 2012
Novell GroupWise 2012 Support Pack 1
Novell GroupWise 2012 Support Pack 2


Server runs out of packet receive buffers (ECB's) and clients can no longer communicate with server.
Mail not showing up on Groupwise clients without a manual refresh.


Add the /udpslap switch to the POA startup file.

Recommended to update to latest released Groupwise Support pack and also continue using the /udpslap switch.  The default option has been changed with Groupwise 2012. 

Additional Information

Up until GW8 clients were notified of updates made to their mailbox by a UDP packet sent from the POA to the client. However, due to packet filtering on some routers and firewalls, some UDP packets would not make it to the client, thus updates such as new mail would not show up on the client without a manual refresh.

GW8 changed this slap packet to a TCP packet. We have found some overhead caused by the change and thus development added the /udpslap switch to use the older method. For the next version of GroupWise a hybrid of the two will be introduced where the POA will default to using UDP unless it can tell that the client is not being responsive to the UDP slaps in which case it will use the TCP method for the duration of the connection.