Время соединения SSH для сервера через брандмауэр?

У меня есть сценарий ~/.ssh/confi для подключения к удаленному серверу (очень удаленному, другому континууму) через брандмауэр:

 Host ras HostName ras.cse.ust.hk User farshidhss ForwardAgent yes ForwardX11 no LogLevel DEBUG3 ServerAliveInterval 10 ServerAliveCountMax 3 Host farshid HostName 10.89.226.143 User luca ForwardX11 no LogLevel DEBUG3 ServerAliveInterval 10 ServerAliveCountMax 3 ProxyCommand ssh -o 'ForwardAgent yes' -o 'ForwardX11 no' ras 'ssh-add && nc %h %p' 

Это странно, потому что в 25% случаев я могу успешно подключиться, но большую часть времени я получаю эти сообщения:

 luca@jarvis:~$ ssh farshid debug1: Executing proxy command: exec ssh -o 'ForwardAgent yes' -o 'ForwardX11 no' ras 'ssh-add && nc 10.89.226.143 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 debug2: resolving "ras.cse.ust.hk" port 22 debug2: ssh_connect_direct: needpriv 0 debug1: Connecting to ras.cse.ust.hk [143.89.40.101] port 22. debug1: connect to address 143.89.40.101 port 22: Connection timed out ssh: connect to host ras.cse.ust.hk port 22: Connection timed out ssh_exchange_identification: Connection closed by remote host 

Почему и как я могу это решить?

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