Host ras
Hostname ras.cse.ust.hk
User farshidhss

Host farshid
ProxyCommand ssh -q ras nc -q0 10.89.100.72 22

luca@jarvis:~$ ssh -xv luca@farshid
OpenSSH_7.2p2 Ubuntu-4ubuntu2.1, OpenSSL 1.0.2g  1 Mar 2016
debug1: Reading configuration data /home/luca/.ssh/config
debug1: /home/luca/.ssh/config line 5: Applying options for farshid
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Executing proxy command: exec ssh -q ras nc -q0 10.89.100.72 22
debug1: permanently_drop_suid: 1000
debug1: identity file /home/luca/.ssh/id_rsa type 1
debug1: key_load_public: No such file or directory
debug1: identity file /home/luca/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/luca/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/luca/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/luca/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/luca/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/luca/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/luca/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.2p2 Ubuntu-4ubuntu2.1