First from Dallas:
270 06:13 PM wang@ns1)dig www.google.com +shortNext from Xi'an, China:
271 06:13 PM wang@ns1)ping -c 2 www.google.com
PING www.l.google.com (220.127.116.11) 56(84) bytes of data.
64 bytes from yw-in-f99.google.com (18.104.22.168): icmp_seq=1 ttl=54 time=21.2 ms
64 bytes from yw-in-f99.google.com (22.214.171.124): icmp_seq=2 ttl=54 time=21.0 ms
[wang@www ~]$ dig www.google.com +shortFinally from Zhejiang China:
[wang@www ~]$ ping -c 2 www.google.com
PING www.l.google.com (126.96.36.199) 56(84) bytes of data.
64 bytes from hk-in-f147.google.com (188.8.131.52): icmp_seq=1 ttl=242 time=45.7 ms
64 bytes from hk-in-f147.google.com (184.108.40.206): icmp_seq=2 ttl=242 time=45.8 ms
137 03:06 PM wang@cn)dig www.google.com +shortYou can see the IP's for www.google.com from these locations are different. The reason for this is that Google want to send www.google.com visitors to their nearest web servers. Why? you might ask. Because of network latency. Here's output from pinging US google server from China:
138 03:06 PM wang@cn)ping -c 2 www.google.com
PING www.l.google.com (220.127.116.11) 56(84) bytes of data.
64 bytes from jp-in-f99.google.com (18.104.22.168): icmp_seq=1 ttl=243 time=47.4 ms
64 bytes from jp-in-f99.google.com (22.214.171.124): icmp_seq=2 ttl=243 time=47.4 ms
[wang@www ~]$ ping 126.96.36.199 -c 2So the ping time is >10 times as long as ping time from within US. If Google doesn't have servers in China (or hk, jp, or whatever closer to China), the experience of Chinese www.google.com visitors will be really bad (long response time, slow page load).
PING 188.8.131.52 (184.108.40.206) 56(84) bytes of data.
64 bytes from 220.127.116.11: icmp_seq=1 ttl=44 time=258 ms
64 bytes from 18.104.22.168: icmp_seq=2 ttl=44 time=261 ms
The 3 popular DNS software (bind, powerdns, tinydns) all have geo capability, either with patch, backend, or in tinydns case, a fork called geoipdns. I have been using Tinydns for several years and very satisfied with its ease of use and performance. So I stick with Tinydns for my geodns.
The geodns fork of Tinydns is called geoipdns, it's written by Adrian Ilarion Ciobanu.
I will talk about how to set up Geoipdns in the next post.
Can you provide the geo location patch for DjbDns.
Post a Comment