SSH Port Forwarding

ssh-port-forwarding

# $HOME/.ssh/config

Host example-forward
  HostName bastion.example.com
  ForwardAgent yes
  ForwardX11 yes
  LocalForward 9090 app-0.example.local:8080

# this allows you to run `ssh example-forward`
# you'll get an SSH session but more importantly,
# requests on localhost:9090 will be forwarded past the bastion onto its local network
# and finally to port 8080 of the app-0 server
# maybe to access the web console of app-0 you'll need to address it as app.example.local
# in which case you should add a line to /etc/hosts:
# 127.0.0.1    app.example.local
# then go on a web browser to http://app.example.local:9090