====== 局域网穿墙 和一些问题 ======
1. https://www.gingerdoc.com/tutorials/how-to-set-up-and-configure-an-openvpn-server-on-ubuntu-20-04

2. http://www.tomato.cm/1153.html

3. https://www.ilxqx.com/archives/jie-jue-openvpn-ke-hu-duan-suo-you-wang-luo-quan-zou-vpn-de-wen-ti

4. https://github.com/OpenVPN/openvpn/blob/master/sample/sample-config-files/client.conf