vnc tunnel through ssh over internet is not working

hi, all:

i have vnc server (remote desktop) and sshd enabled. the machine is behind my fios home gateway and i have enabled port forwarding for both ssh and vnc port 5900 (set vnc port as 5900). on client machine (windows 7), i have putty installed


my goal is to have vnc session tunneled over ssh, from win7 to the machine at my house.


here are three tests that worked so far:



1) ssh sessions work perfectly as itself. from my office to my house. no vnc client involved.

2) vnc clear text session itself also works fine, from my office to my house. i was using tightvnc vnc viewer; remote host on the viewer was set as "unix.domain.com:5900". no ssh session involved.

3) on the same subnet, ie, both vn client and vnc server were on the same subnet (no firewall involved). it also works. on win7 machine, i started ssh session first, then started vnc viewer with setting of "localhost:1". it works as designed.


now here is what doesn't work:

tunneling vnc over ssh session crossing the internet, from my office to home. in this case, on win7 machine, i started a ssh session to the macbook (from my office) and it connected to vnc server with no issues. then i started vnc viewer, with setting as "localhost:1" as before. for some reason, i always get message "Connection has been gracefully closed", which i interpret this message as the tunneled vnc session reached vnc server but somehow closed by vnc server.

any help would be greatly appreciated.

thanks


_dave