The steps bellow are from From TN 1441275
To resolve the problem perform the following steps
- The TCP stack in Windows 2008 has a few new features that are not yet supported by every
hardware. The following configuration changes will set the TCP stack to work in a more "conventional" way. To do so, type from command line:
netsh int tcp set global autotuninglevel=disabled
netsh int tcp set global rss=disabled
netsh int tcp set global chimney=disabled
netsh int tcp set global congestionprovider=none
A reboot is needed after making this changes.
- For Sametime 8.5.1, set the following flag under the [Config] section of the sametime.ini file:
This setting is set automatically during install of 8.5.2 on Windows 2008.
For 8.5.0, a hotfix, LKRK-86RGNA, is available for part of the components: STCommunity, STMux, STOnlineDir, STUserStorage. Open a service request with IBM Support to determine if this hotfix is applicable for your environment if you are not able to upgrade to 8.5.1 or later.