Step 1: SSH Command
SSH -i ./.ssh/sj03 user@domain.com
Step 2: Add -N to Network Port forward
SSH -i ./.ssh/sj03 user@domain.com -N
Step 3: Add -L if tunnel starts on Local
SSH -i ./.ssh/sj03 user@domain.com -N -L 8888
Step 4: Add -R if tunnel starts on Remote
SSH -i ./.ssh/sj03 user@domain.com -N -R 80
Step 5: Open local 8510 port and forward to <remote-server-ip-you-want-to-connect> on port 22:
SSH -i ./.ssh/sj03 user@domain.com -N -L 8510:<remote-server-ip-you-want-to-connect>:22
Step 6: Now, local port is open , connect your server
SSH -i ./.ssh/sj03 user@localhost -p 8510
