The following command can be used to create a SSH Tunneling which forwards any connection to port 1234 on the local machine to port 4321 on localhost via example.com

ssh -N -L 1234:localhost:4321 -p 22 -i ~/.ssh/id_rsa username@example.com


For more information about the flags, please refer https://explainshell.com/explain?cmd=ssh+-L+-N++-f
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