ssh user@hostname -L <localport>:<dst_hostname>:<remoteport>
e.g.
ssh user@hostname -N -L 8888:127.0.0.1:8888
from https://linuxize.com/post/using-the-ssh-config-file/
mkdir -p ~/.ssh && chmod 700 ~/.ssh
touch ~/.ssh/config
chmod 600 ~/.ssh/config
Host hostname1
SSH_OPTION value
SSH_OPTION value
Host hostname2
SSH_OPTION value
Host *
SSH_OPTION value