Problem: Terminal Server Refuses New Connections
Error: Event Log Shows 'The terminal server received a large number of incomplete connections. The system may be under attack.'
Problem is caused by too many logon /logoff actions at the same time.
Obviously this could be caused by an attack but if you're like me, it was caused by too much activity at once.
In HKLM\System\CurrentControlSet\Control\TerminalServer , add the following DWORD value: MaxOutstandingConnect
You will need to add the value in hexadecimal format.
50 is entered as 32 hex
75 is entered as 4b hex
Then reboot the server and your issue is resolved.
This has been tested and validated on the following OS's:
Windows Server 2008
Windows Server 2008 x64
Windows Server 2008 R2