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We know that we can specify Local or Dynamic Port Forwarding through ssh by specifying command-line parameters:
ssh -D #### \ # For Dynamic Forwards
-L ####:host:#### # For Local Forwards
But if I forget to specify a forward, can I somehow add one during the session, without having to close the connection and start a new session?
PuTTY (on Windows) can do this, but ssh is a different application.
As I discovered in a comment on a similar question, ssh supports the EscapeChar, which is the tilde (~) character by default. With this EscapeChar, you can perform many tasks, including the modification of Port Forwarding. The EscapeChar only works following a new line, so you may need to insert a newline (i.e. by pressing enter).
Assuming that ~ is the EscapeChar, ~? will list the available options. The SSH command line provides the interface to add a new port forwarding route, with ~C. To add a Local or Dynamic Forward, use:
~C
ssh> -L ####:host:####
Forwarding port.
~C
ssh> -D ####
Forwarding port.
# Even without a prompt, your input has returned to the remote session
ssh client. You can add it to your client-side ~/.ssh/config file under a Host section as LocalForward #port# host:#port# or DynamicForward #port#.
bash script to it.
Mar 5, 2021 at 7:52