ssh -L 10002:192.168.0.30:10002 192.168.1.135 to establish port forwarding but now I need to remove it.
How do I do this?
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When using ssh multiplexing, killing the ssh process is often undesirable (it kills all open connections with that host), and you cannot easily access the escape because "escape not available to multiplexed sessions". The right way is then to run the analogue of the forwarding command that you want to cancel, but adding
-O cancel. For instance:
ssh -O cancel -L 10002:192.168.0.30:10002 192.168.1.135
This will disable this port forwarding without terminating the session. Again, this will only work if ssh multiplexing is in use for the connection to 192.168.1.135.
You can enter an interactive console by typing ~C (capital "C"). This lets you dynamically add and remove port forwardings (among a few other things).
This sequence has to come right after a carriage return/newline. So in doubt, just type Enter~C (in sequence).
If you don't see the characters appear on the console, you're doing it right :)
You should now see an
To remove the port, simply enter
-KL 10002 followed by Enter (where
10002 is your forwarded port).
The inverse - adding a new forward - can be done like this (from start to finish):
ssh> -L 10002:192.168.0.30:10002