use jumphost with ssh proxy command

config

Host *
  ControlMaster auto
  ControlPath ~/.ssh/tmp/%h_%p_%r
  TCPKeepAlive yes
  ServerAliveInterval 30
  ConnectTimeout 15
  LogLevel ERROR

Host jumphost
  HostName ${JUMPHOST_IP}
  User ${JUMPHOST_USER}
  IdentityFile ${JUMPHOST_PRIV_KEY}
  ProxyCommand none

Host ${SERVER_IP_GLOB}
  User ${SERVER_USER}
  IdentityFile ${SERVER_PRIV_KEY}
  ProxyCommand ssh -e none jumphost exec nc -w 60 %h %p 2>/dev/null