Users are experiencing RDP session disconnected randomly when connected remotely to servers via RDP session. Checking at the event log. You will see the following errors:
EventID 56 : Source TermDD
The Terminal Server security layer detected an error in the protocol stream and has disconnected the client. Client IP: X.X.X.X
EventID 50 : Source TermDD
The RDP protocol component X.224 detected an error in the protocol stream and has disconnected the client
I did some research and found the following:
http://blogs.technet.com/b/askperf/archive/2010/03/25/the-curious-case-of-event-id-56-with-source-termdd.aspx
http://social.technet.microsoft.com/Forums/en-US/winserverTS/thread/ab950c6e-847a-4f51-bc15-b9f54793787c
Suggested cause of actions are:
1. Disable Autotunning in the TCP to determine any improvement: Open up an elevated command prompt and issue the following command.
netsh interface tcp set global autotuninglevel=disabled
netsh interface tcp set global autotuninglevel=normal
(this will reverse the change if you find it has adverse effects.)
netsh interface tcp show global
(to show the TCP settings)
2. Set the MTU to 1300 (Default is 1500)
netsh interface ipv4 show interface
netsh interface ipv4 set subinterface "Local Area Connection" mtu=1300 store=persistent
I carried out with some test and couldn’t come to a conclusion with this. After adjusting the MTU size, I managed to keep the RDP connection for over 2 days now without disconnection. I will have to keep monitoring this one.
