Posted
by
Bink on
on August 6 2008, 1:16 PM
with no comments
Last month I had a client buy and install several Dell PowerEdge 2950 servers. These servers had 2 Quad processors, 16GB or RAM, and 2 300GB 15K RAPM SAS hard disks, making them ideal for medium-range departmental servers. When the machines arrived, I installed Windows Server 2008 Standard Edition 64-bit on them, and proceeded to configure them based upon the client's needs.
One of the machines was installed as a Domain Controller. Another was configured to host a SQL database, and 3 more were to act as Virtual Server machines. At that time. Microsoft has not yet released Hyper-V as RTM, and I decided against deploying it at an RC1 phase on that client's network. So instead, I installed Microsoft Virtual Server 2005 R2 SP1 (with the KB948515 update). All machines were configured to allow remote administration through RDC (Remote Desktop Connection).
At first all seemed well. However, after some time, I began seeing strange network issues. Sometime the servers would just lose connectivity. Their NICs where in a "Connected" status, they had static IP addresses assigned, but they would sometimes lose Internet connectivity. The Virtual Machines hosted on these servers would act even more erratically. They sometimes lost connectivity with the host server, sometimes responding to PINGs, sometimes losing it. Furthermore, each VM was accessed through RDC, and whenever I tried to use the RDC client (mstsc.exe) to connect to the VM, every second attempt would fail. I would press "Connect" and it would just sit there doing nothing. Pressing "Connect" again would sometimes work, and sometimes fail.
The servers themselves worked flawlessly, but connecting to the host OS with RDC would sometimes freeze, and in most cases it would disconnect me with this error message:
Remote Desktop Disconnected
Because of an error in data encryption, this session will end. Please try connecting to the remote computer again.
The nasty part was that this error only appeared when connecting to the servers from my Vista SP1 laptop. All other computers on the network had no issues when connecting to the remote servers.
I have changed from Remote tab for System Properties on both the 2008 Server and Vista system to have a more secure and less secure session and it doesn't seem to matter.
After some looking around I discovered that uninstalling VS2005 on one of the servers solved the issue of network disconnections for that server, but I needed it so I looked further. Luckily for me, at that same time, Microsoft released Hyper-V RTM, so I decided it was a good opportunity to use it instead of Virtual Server 2005. Furthermore, some posts on various forums and newsgroups on the Internet said it had nothing to do with VS2005. So I needed to investigate further.
After some more digging it turns out that the blame is on the server's NIC – a Broadcom BCM5708C NetXtreme II GigE.
In order to fix the RDC disconnection issues you need to disable the IPv4 Large Send Offload setting in the NIC's properties.
Continue At Source
12321 Views