dqjdda牛人大佬：
vi /etc/resolv.conf

直接改为

1. search host
2. nameserver 195.46.39.39
3. nameserver 77.88.8.7
4. nameserver 8.8.8.8
5. options timeout:3 attempts:3

延迟对比：

1. root@vm:~# ping 195.46.39.39（safedns）
2. PING 195.46.39.39 (195.46.39.39) 56(84) bytes of data.
3. 64 bytes from 195.46.39.39: icmp_seq=1 ttl=54 time=25.6 ms
4. 64 bytes from 195.46.39.39: icmp_seq=2 ttl=54 time=24.5 ms
5. 64 bytes from 195.46.39.39: icmp_seq=3 ttl=54 time=26.3 ms
6. 64 bytes from 195.46.39.39: icmp_seq=4 ttl=54 time=24.6 ms

1. root@vm:~# ping 77.88.8.7 (Yandex.DNS)
2. PING 77.88.8.7 (77.88.8.7) 56(84) bytes of data.
3. 64 bytes from 77.88.8.7: icmp_seq=1 ttl=54 time=101 ms
4. 64 bytes from 77.88.8.7: icmp_seq=2 ttl=54 time=101 ms
5. 64 bytes from 77.88.8.7: icmp_seq=3 ttl=54 time=101 ms
6. 64 bytes from 77.88.8.7: icmp_seq=4 ttl=54 time=103 ms

1. root@vm:~# ping 8.8.8.8（谷歌DNS）
2. PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
3. 64 bytes from 8.8.8.8: icmp_seq=1 ttl=101 time=113 ms
4. 64 bytes from 8.8.8.8: icmp_seq=2 ttl=101 time=113 ms
5. 64 bytes from 8.8.8.8: icmp_seq=3 ttl=101 time=113 ms
6. 64 bytes from 8.8.8.8: icmp_seq=4 ttl=101 time=114 ms

牛人大佬们可以对比测试下

WooSi牛人大佬：
1111呢