Citrix traffic is very slow thru Novell BorderManager 3.9

Customer was running Novell BorderManager 3.8 on Novell Netware 6.5 sp7 and using the generic proxy to allow Citrix traffic thru BorderManager with no issues. After upgrade to Novell BorderManager 3.9 support pack 1, Citrix traffic is very slow. Typing some words in MS word, for example, takes 2-3 seconds to appear on screen, causing an annoying delay. If generic proxy is bypassed and static Nat used, problem disappeared.

This issue has been fixed in two files:

1. Proxy.nlm dated 2-feb-2009 and included in Novell BorderManager 3.9 Support Pack 2.
2. Tcpip stack (domestic version) included in Novell Netware 6.5 Support Pack 8.

Both files are needed to solve the issue.

The culprit of the slowness was caused by the fact that generic proxy was removing the PUSH flag from the TCP header causing the MS windows stack to buffer the information instead to pass it on to the application. Once the above mentioned files were put in place, PUSH flag was preserved and the MS windows stack did not buffer anymore, hence the delay was gone.