Friday, December 18, 2009

Google Public DNS - Speed Up Application User Experience

Google Public DNS is primarily aimed at users of the internet. I had run across it surfing the web and filed it away. But it wasn't until my configured DNS servers for my local network went down (again) that I decided to give it a shot.

A couple of things that I notice right away is that the IP addresses are easy to remember:

8.8.8.8 and 8.8.4.4


That's actually something I am going to be able to recall next time I find myself with broken DNS services. The second thing is that my ping to these are 24ms roughly, that's not too bad. The real test is lookup speed, and this is where Google is riding on the edge as they appear to be doing some aggressive pre-lookup of DNS entries on slow DNS servers. Are they going to break TTL? A lot of people design fail-over using a lower TTL in their DNS responses so that the cache will be flushed if a failover is needed to a new IP address.

In any case, I've giving it a go for a while and so far my surfing does feel faster.

So if your public facing users are complaining about a slow web experience on your site, one suggestion is to point them to the free Google DNS servers to see if that improves their experience.

4 comments:

cmercer said...

I use opendns.com so that I can control the filter of "bad" things on the internet. Kind of nice if you have kids who are not too old or too technical to get around it.

The speed was much better than the my isps dns too.

cmercer said...

opendns.com blog on google dns

http://blog.opendns.com/2009/12/03/opendns-google-dns/

Shawn said...

Pinging 8.8.8.8 with 32 bytes of data:
Reply from 8.8.8.8: bytes=32 time=23ms TTL=245
Reply from 8.8.8.8: bytes=32 time=28ms TTL=245
Reply from 8.8.8.8: bytes=32 time=29ms TTL=245
Reply from 8.8.8.8: bytes=32 time=29ms TTL=245

vs.

Reply from 208.67.222.222: bytes=32 time=39ms TTL=54
Reply from 208.67.222.222: bytes=32 time=40ms TTL=54
Reply from 208.67.222.222: bytes=32 time=43ms TTL=54
Reply from 208.67.222.222: bytes=32 time=40ms TTL=54

It looks like, for me anyway, Google latency is about 40% better. But I really do like the filtering feature of OpenDNS so I will give it a try.

Shawn said...

OK, switched to OpenDNS.com and I really like the filtering. Now can keep kids from getting to playboy.com and it's faster, more reliable than ISP DNS server.

I do like the privacy of OpenDNS although my guess using Google will give you faster surfing, would probably need to test that.