记录下两个免费的DNS
> set type=a
> resolver1.opendns.com
Server: [208.67.222.222]
Address: 208.67.222.222
Non-authoritative answer:
Name: resolver1.opendns.com
Address: 208.67.222.222
> resolver2.opendns.com
Server: [208.67.222.222]
Address: 208.67.222.222
Non-authoritative answer:
Name: resolver2.opendns.com
Address: 208.67.220.220