ssh config

# Simple "jump box" scenario
#   For any user with the same userid on all three systems
#     jump from source.example.com to dest.example.com via jump.example.com 
#     using default ports
#     using local keys (e.g. ~/.ssh/id_rsa on source.example.com)
#
#   English: ssh from source.example.com to dest.example.com when dest.example.com is not 

# using a ssh
Host jump-to-dest
  Hostname dest.example.com
  ForwardAgent yes
  ProxyCommand ssh -W %h:%p jump.example.com