To disable it
echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
Permanently
# echo '"# Disable TCP window scaling" > sysctl.conf'
# echo '"net.ipv4.tcp_window_scaling=0" >> sysctl.conf'
Also see http://www.ecr6.ohio-state.edu/window-scaling.html.
Fedora, Red Hat, CentOS, Linux
echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
# echo '"# Disable TCP window scaling" > sysctl.conf'
# echo '"net.ipv4.tcp_window_scaling=0" >> sysctl.conf'