'cancel-tcpip-forward' is not supported.

[Dan Kaminsky]

>Is there a plan to support that request?  Without that,
>ssh clients can not cancel '-R' port forwardings dynamically.
>  
>
Atsuhiko--

    Back in the SSHv1 days, common ssh daemons couldn't declare remote 
port forwards after a shell was opened.  I never checked what happened 
with SSHv2; it sounds like we allow on-demand opens but not 
closes...guys, what do you think?  It's in the spec, and it's pretty 
clearly a useful feature...

--Dan