SSH clients periodically freeze under Windows 7

Solution 1:

I use putty under windows and do not have this issue. There is nothing intrinsic to windows that would cause this issue. It could be something like symantec antivirus firewall or another piece of software that is interupting the connection.

Solution 2:

The described problem was very annoying too. I tried approach with disabling Large Send Offload and Jumbo Packet as was suggested above (as well as other options in network adapter properties > advanced tab). Unfortunately, the positive result was only "short-time": after adapter reboot, which is necessary to activate chosen adapter options, everything was fine, but then after some time (several minutes) ssh session became laggy/with freezes.

The observed behavior ("smooth" SSH immediately after adapter reboot and laggy after some time) suggested to look at power-saving options. Finally, the problem was solved disabling "Allow the computer to turn off this device to save power" option in Device Manager > Network adapters > adapter properties > Power Management. The problem/solution was successfully reproduced after enabling/disabling this option (the result is seen after some minutes without adapter reboot).

The approach was tested on the following software setups: SSH Secure shell on Windows 7 Professional 64-bit and Putty on Windows 7 Ultimate 64-bit both connected to different Linux servers.