[network] SOCKS5 proxy in Linux

1. add host info in ~/.ssh/config

$~/.ssh$ cat config
host <host_name>
hostname <host_ip>
user <user>
DynamicForward <forward_port>
identityfile <id_rsa_private_key>

2. modify the permission of file <id_rsa_private_key>

$ chmod 600 <id_rsa_private_key>

3. open the socks5 proxy

$ ssh -CfnNqT <host_name> -vv

4. on agent, config a port <forward_port>