May 06, 2006
Memorable DNS IPs
Comcast has ocassionally messed up its DNS servers - last year they had a series of systemwide DNS outages that lasted several days. (My Comcast DNS servers are 184.108.40.206 and 220.127.116.11.)
Today Comcast DNS is being slow - but not out. That is good, because it means I can still get to Google and I can still use it to find other DNS servers.
For future reference: if my DNS servers ever go out, I will use the following DNS servers with easy-to-remember IP addresses - thanks to AT+T and Level 3:
18.104.22.168, 22.214.171.124, 126.96.36.199, 188.8.131.52, 184.108.40.206, 220.127.116.11
Here in Pennsylvania, these servers are all just as close as Comcast's DNS servers to me, < 20ms ping, and they are serving DNS faster today.
Update Apparently Reza also uses the same DNS IP addresses in Seattle with good results, which seems remarkable. Curious, I collected some roundtrip numbers to 18.104.22.168 from various computers I use:
|From Philadelphia, PA||18 ms|
|From Washington, DC||13 ms|
|From Mountain View, CA||3 ms|
The evidence seems to contradict the laws of physics. It takes 32ms for a photon traveling at the speed of light to bounce from the U.S. Northeast to the West Coast and back again; in practice you're doing extremely well if you can get through all the routers in twice that (for example my DC and CA computers have a 94ms ping time between them). But 3+13=16ms is much less than 32ms and a physical impossibility. Even with perfect zero latency routers and perfectly straight-line optical paths, a 16ms round-trip is twice as fast as possible.
Perhaps there is a very clever predictive algorithm in San Jose that knows how to send a reply 40ms before receiving the request? Or perhaps Level 3 has installed top-secret quantum time-warp hardware at 22.214.171.124? Or maybe 126.96.36.199 is using Robert Boyd's magical erbium glass fiber?
It turns out that 188.8.131.52 routed using "anycast," which is a kind of routing that lets servers distributed around the world to be assigned to the same IP address - something that is usually a no-no. Most big web servers use round-robin DNS for load-balancing, which is where there is more than one IP address that can answer to the same DNS address. But since you can't rely on DNS lookup to distribute load for DNS servers themselves, anycast is the alternative. Interesting.
Update 9/5/2006: 184.108.40.206 was having trouble yesterday.
For future reference, the OpenDNS servers are:
And they are quite fast! (They also come with some weird features like anti-phishing redirect, etc, which is both a plus and a minus depending on what you want to do.)
In recent years I've been using Google's DNS servers - also easy to remember. No redirections, and Google is serious about speed and security.
Posted by David at May 6, 2006 07:01 AM
I had the same situation here in Seattle last year and switched to the same IP that you are using:
They all use IP Anycast - in otherwords, identical servers scattered around the network with the same IP. These IP's are announced- and their IGP choses the shortest path to the 'nearest' server.
www.nanog.org has some nice preso's on DNS Anycasting.
We also use anycast at OpenDNS and with an account you can manage your preferences and have insight into the DNS unlike you've ever had before. It's powerfully cool stuff.
Belive it or not ping returns an average of 16ms to 220.127.116.11 - and that is from the United Kingdom
As you say, strange but true
12ms from Portland, Oregon
I have been using 18.104.22.168 for a few years now as well and was talking to an apple rep a few days ago, who was also using the same dns servers. I decided to google the IP and found your site.
FYI I had great speeds in locations across Japan, Guam, Hawaii, Canada and pretty much any location I was in.
The IP is hard coded into my brain.
Today Charter communication's was having noticable DNS issues...so i called the tech department,
"what DNS are you using?"
"22.214.171.124 (Charter's for the area)"..
"Oh no sir you should be using 126.96.36.199..."
"Really? since when do you piggyback on Level3's DNS?"
"Those are Charter's DNS sir"
"Wow, since...nah forget it, Thank you for verifying that you are in fact having DNS issues, goodbye."
Ran across your site looking for some history on these infamous DNS servers. Thanks.
This is the Googles free DNS service
@SK: no this isn't. Google is providing free DNS service on the IPs 188.8.131.52 and 184.108.40.206
technically still owned by LEVEL 3:
220.127.116.11 - 18.104.22.168
not google. do a whois look-up and see for yourself.
Technically, the 22.214.171.124/24 network is allocated to Google:
$ whois 126.96.36.199
Level 3 Communications, Inc. LVLT-ORG-8-8 (NET-8-0-0-0-1) 188.8.131.52 - 184.108.40.206
Google Incorporated LVLT-GOOGL-1-8-8-8 (NET-8-8-8-0-1) 220.127.116.11 - 18.104.22.168
Thank you so much, like omg, so much help u have been...
Iam locked out of directs on my table with level 3 acces, admin on bluetooth I've never used. Lfp
If you're using 22.214.171.124 - 126.96.36.199 (for awhile just 188.8.131.52 was not working) you will get dns hijacked/redirected to http://searchguide.level3.com/ when you visit a domain that does not resolve.
Since it's a big part of the fabric of the internet, they didn't want to shut it down, so they're now trying to profit from it. In a way, I don't blame them, since so many people are using it worldwide.
More details on tummy's article called famous dns server