I'm still having connection drops. From the logs it seems to happen every 20 minutes. The strange thing though is that not all clients having those drops.
Log file info:
2012-09-23 20:37:25,199  INFO CKS Server - Session: 809a9d4c-41a8-4d64-868f-3856d47b0073/***.***.****.***:3186
New SocketSession was accepted!
2012-09-23 20:37:25,331  INFO CKS Server - 30100 succesvol aangemeld
2012-09-23 20:37:25,478  INFO CKS Server - 30100 invoked getserver method.
2012-09-23 20:57:25,868  INFO CKS Server - Session: 809a9d4c-41a8-4d64-868f-3856d47b0073***.***.****.***:3186
This session was closed!
From client side no close command is initiated.
BTW i'm using 1.4 SP4 and NetMicroframework as client.