我在 tun0 (Ubuntu 16/EC2) 上使用 OpenVPN，我可以使用systemctl start openvpn@Ireland（PIA 的爱尔兰集群）成功启动它，但该接口无法访问 Internet：
curl --interface tun0 -vv http://icanhazip.com/plain
* Trying 104.20.17.242...
* Local Interface tun0 is ip 10.34.10.6 using address family 2
* Local port: 0
* Trying 2400:cb00:2048:1::6814:10f2...
* Trying 2400:cb00:2048:1::6814:11f2...
* Trying 2400:cb00:2048:1::6814:10f2...
* Trying 2400:cb00:2048:1::6814:11f2...
这是我的 /etc/openvpn/Ireland.conf：
client
dev tun
proto udp
remote ireland.privateinternetaccess.com 1198
resolv-retry infinite
nobind
persist-key
persist-tun
cipher aes-128-cbc
auth sha1
tls-client
remote-cert-tls server
auth-user-pass
comp-lzo
verb 1
reneg-sec 0
crl-verify crl.rsa.2048.pem
ca ca.rsa.2048.crt
disable-occ …