3.8.5 Strange access problems with some websites

Recent Linux kernels enable ECN by default, which may cause access problems with some websites on bad routers. To check ECN status:

     # cat /proc/sys/net/ipv4/tcp_ecn
      ... or
     # sysctl net.ipv4.tcp_ecn

To turn it off, use:

     # echo "0" > /proc/sys/net/ipv4/tcp_ecn
      ... or
     # sysctl -w net.ipv4.tcp_ecn=0

To disable TCP ECN on every boot, edit /etc/sysctl.conf and add:

     net.ipv4.tcp_ecn = 0