SSH config using proxy / jumbox / bastion

config

Host your-jumpbox
    HostName xxx.xxx.xxx.xxx
    User user1
    IdentityFile ~/.ssh/private_key_for_jumpbox

Host endpoint1
    HostName xxx.xxx.xxx.xxx
    User user2
    ProxyCommand ssh -q -W %h:%p your-jumpbox

Host endpoint2
    HostName domain.to.endpoint2
    Port 1234
    User user3
    IdentityFile ~/.ssh/private_key_for_endpoint2
    ProxyCommand ssh -q -W %h:%p your-jumpbox
    ServerAliveInterval 50 # Prevent server to drop user (AWS)