OSX Lion terminal X11 connection broken 문제

X connection to localhost:18.0 broken (explicit kill or server shutdown).

 snow leopard에서 잘사용했었는데..

ssh -X 로 접속해서 X서버를 땡겨 쓰고 했는데.
lion으로 업그레이드 하고 나니 위와 같은 에러가 가끔씩 난다

한번 나고 나면 서버에 있는 GUI프로그램을 사용할 수가 없다.

man ssh를 하면 아래와 내용을 볼 수 있다.
-X      Enables X11 forwarding.  This can also be specified on a per-host
             basis in a configuration file.

             X11 forwarding should be enabled with caution.  Users with the
             ability to bypass file permissions on the remote host (for the
             user’s X authorization database) can access the local X11 display
             through the forwarded connection.  An attacker may then be able to
             perform activities such as keystroke monitoring.

             For this reason, X11 forwarding is subjected to X11 SECURITY
             extension restrictions by default.  Please refer to the ssh -Y
             option and the ForwardX11Trusted directive in ssh_config(5) for
             more information.

     -x      Disables X11 forwarding.

     -Y      Enables trusted X11 forwarding.  Trusted X11 forwardings are not
             subjected to the X11 SECURITY extension controls.

-Y 옵션으로 접속하면  trusted X11 forwarding 이라고 한다.
실제로 아직까지는 연결 끊김 없이 잘 사용되고 있다.