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Opendns Vs Google Dns

Tywais

By Tywais
in IT and Computers

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Tywais Star Member

Tywais

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Recently we had problems accessing one of our research web sites with indications it was down. However, using another server in the US it was available so my focus was on DNS issues. I run a DHCPD server and have OpenDNS as the DNS server IP that loads on the lab computers. My office computer though has a fixed IP as it it performs server functions also, such as file services but had the same problem.

Decided to change my network setting DNS from OpenDNS to Google DNS and the site worked perfectly. Reconfigured the DHCPD to supply Google DNS IPs, reset the dhcp daemon, and now the site is accessible from all computers and it is fast.

So, if having problems with DNS or find OpenDNS to be problematic I recommend Google DNS. The IPs are 8.8.8.8 and 8.8.4.4

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welo Gold Member

welo

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I am experimenting with different DNS as well. One problem I encountered is that when your ISP has serious network troubles and some IPs are not reachable or often timeout, switching to an alternative DNS completely might bring you additional troubles in such cases.

This happened to me just recently on 3BB - had changed to Google DNS but then the ISP had some serious issues and the Google DNS timed out 9 out of 10 times. However, this did not apply to all IPs (websites), and switching back to 3BB's own DNS servers 'fixed' the problem in the sense that since DNS resolving worked again I could at least access those IP ranges/networks that were not affected by the routing problem.

Long story short, I guess it is a good idea to add Google/openDNS/dnsAdvantage as primary DNS, and your ISPs server as backup DNS.

welo

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Pib Star Member

Pib

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I've been using the Google Public DNS servers for about a month now with good results; I can now reach sites that I couldn't before when using my ISP's (JI-NET) DNS server. After reading some posts where some folks gave OpenDNS high marks also I decided to set my Secondary DNS server to OpenDNS 208.67.222.222 and keep my Primary DNS set to the Google DNS 8.8.8.8 That way I have a different DNS server as my backup/secondary (OpenDNS in this case) in case I can't reach my primary DNS server (Google DNS). I don't want to use my ISP's DNS server as I already know it can't reach certain sites. I didn't notice any browser speed differences regardless of the DNS server being used; the only difference was the ability to reach certain/all sites.

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Tywais Star Member

Tywais

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Google DNS - just another data collector for them :) They read your mails, they know the sites you visit and perhaps much more already. I will not use this service for sure.

Perhaps you are not aware but if in Thailand your ISP is maintaining logs of your IP and traffic history as required by Thai law. I would be more concerned with that then Google. This is the privacy statement of Google DNS

Privacy statement:

1. What information does Google log when I use the Google Public DNS service?

Google Public DNS complies with Google's main privacy policy, which you can view at our Privacy Center. With Google Public DNS, we collect IP address (only temporarily) and ISP and location information (in permanent logs) for the purpose of making our service faster, better and more secure. Specifically, we use this data to conduct debugging, to analyze abuse phenomena and to improve our prefetching feature. After 24 hours, we erase any IP information. For more information, read the Google Public DNS privacy page.

2. Is any of the information collected stored with my Google account?

No.

3. Does Google share the information it collects from the Google Public DNS service with anyone else?

No.

4. Is information about my queries to Google Public DNS shared with other Google properties, such as Search, Gmail, ads networks, etc.?

No.

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Pib Star Member

Pib

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Quote:

Google DNS - just another data collector for them :) They read your mails, they know the sites you visit and perhaps much more already. I will not use this service for sure.

End Quote.

Good idea. Just use whatever DNS provider you currently use because I'm sure they don't track web sites visited. Speaking of web sites visited I'm sure the web sites you do visit are not tracked by cookies, other web service trackers, etc (yea, I'm being a little sarcastic here).

I would much rather be using Google and/or OpenDNS which are USA companies that fall under the privacy protection laws of the U.S. versus the weak privacy protection laws in Thailand. And besides, these two DNS companies/servers work a lot better than my Thai ISP DNS.

Edited by Pib
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Pib Star Member

Pib

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Google gets just too powerful. One Microsoft is enough... But cookies - there are many tools for blocking them. There is even a Firefox add-on from Google to get rid of Google :)

http://www.google.com/ads/preferences/plugin/

Here is a neat little DNS Benchmarking tool to compare the speeds of different DNS servers from your location.

http://www.grc.com/dns/benchmark.htm

The program downloaded is small, only 154KB. Download it to our Windows Desktop and run it. The program has a bunch of DNS servers already loaded for benchmarking. It takes about 5-10 minutes to run the complete benchmarch against the various DNS servers loaded, which include Google DNS and OpenDNS. But during the benchmarch it shows real time results. Excluding my ISP's DNS server which has problems in finding some websites and which I added to the benchmark test, my running of the test resulted in Google DNS as the clear speed winner from my location here in Bangkok.

Edited by Pib
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welo Gold Member

welo

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Well, after my recent research on Steve Gibson I am not exactly one of his admirers. DNS Benchmark seems to be a nifty tool though, people with a vaster knowledge of DNS and benchmarking techniques will hopefully review and comment on it soon.

Alternatively one can use namebench, which btw is OpenSource (and not written in Assembler, so programmers can actually review the code :) ).

A nice feature of this tool is that it takes your Firefox history to create the sample data used in the benchmark. I guess this is not overly important but might be more accurate if your surfing habits are very non-(US)-standard.

This is the result on a friend's 4MBit 3BB line in Samut Prakan (see attachments).

GoogleDNS is faster here than openDNS. Only openDNS has no 'noAnswer', not sure if this is due to openDNS responding with a customized 'not found' page in such cases...

post-73027-1268502778_thumb.jpgpost-73027-1268502784_thumb.jpg

Btw don't get into nit-picking here, DNS lookup times depend on server and network load. Just like with speed tests you should run multiple tests over several hours/days to get real-world results.

Another interesting issue that came up is that of openDNS redirecting Google to its own servers. This seems to be a well know fact (articles dating back to 2007) and heavily discussed in the openDNS forums, openDNS explains and defends this behavior here.

If you decide to dig into this make sure you read the comment posted by Swoop and the reply by openDNS - I don't really understand how I can still end up on Google's website when the DNS lookup returns a openDNS server - do they redirect to Google or act as a Proxy?

I verified the behavior today and it is still in place, check my nslookup session...

C:\Users\welo>nslookup
Default Server:  UnKnown
Address:  192.168.1.1

> server 208.67.222.222					<- switching to openDNS server here
Default Server:  resolver1.opendns.com
Address:  208.67.222.222

> www.google.com
Server:  resolver1.opendns.com
Address:  208.67.222.222

Non-authoritative answer:
Name:	google.navigation.opendns.com	  <- HIJACK!
Addresses:  208.67.219.230
	  208.67.219.231
Aliases:  www.google.com

> server 202.69.137.137				  <- switching back to 3bb/maxnet server here
Default Server:  cns1.tttmaxnet.com
Address:  202.69.137.137

> www.google.com
Server:  cns1.tttmaxnet.com
Address:  202.69.137.137

Non-authoritative answer:
Name:	www.l.google.com			   <- OK
Addresses:  64.233.181.104
	  64.233.181.106
	  64.233.181.147
	  64.233.181.103
	  64.233.181.99
	  64.233.181.105
Aliases:  www.google.com

Will checkout Gibson's tool tomorrow..

welo

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kudroz Silver Member

kudroz

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The principle behind a DNS cache server made a lot of sense 3 years ago - not anymore. It's always a good thing to get your domain resolved a few millisecond faster, but now with more sites using Content Delivery Networks (CDNs), OpenDNS will send you off downloading content in the states while you could download it locally from Thailand.

I'll explain,

When you visit Facebook, YouTube, Flickr, and other media rich sites, their content is likely hosted on CDNs. The video you are watching on YouTube or that picture you're viewing in Facebook is available for download from a "cache" (a replica) server in Bangkok.

Generally speaking, you will directed to the nearest cache server based on your DNS physical location. If you are using OpenDNS to resolve Flickr.com, it means that you will be downloading Flickr's content from a US content cache server; where as if you were using your Thai ISP DNS servers you would be downloading from Bangkok instead - at a much faster speed.

Here is a test here to illustrate my premise

Using OpenDNS (OpenDNS directs me to US cache server)

http://mlone.ak.takecdn.com/100MB.zip

Average speed: 163.8 KB/s

Elapsed time: 10 minutes 25 seconds

Using 3bb DNS (3bb DNS directs me to Bangkok cache server)

http://mlone.ak.takecdn.com/100MB.zip

Average speed: 499.7 KB/s

Elapsed time: 3 minutes 24 seconds

post-25545-1268507469_thumb.jpg

By using my ISP DNS servers I was able to save 7 minutes for a 100MB download. This was performed with my 3BB 5mbps Premier ADSL line.

Edited by kudroz
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Pib Star Member

Pib

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After using both benchmarking programs mentioned above I've decided to use Google as my Primary DNS server and my ISP provider's DNS server as my Secondary DNS server. Before I was using OpenDNS as my Secondary DSN server but it keeps coming in a distance third or lower in speed and indicates some faults/miss-directed results. Although my ISP's provider DNS does not reach a few sites important to me, I figure having my ISP provider's DNS server loaded is probably not a bad idea to maybe make my system work better 24/7.

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welo Gold Member

welo

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@kudroz

This sounds absolutely reasonable to me, I have to revise my post on the other thread that there is NO relation between DNS and download speeds. Of course the two are connected in a different way than most people think.

However, I guess we have to understand better how CDN works, and how DNS server providers react to that issue.

I wonder if GoogleDNS would work with in Thailand. I didn't find any source where exactly their servers are located, but in my tests I found GoogleDNS fastern than openDNS, maybe they have a server in South East Asia or even Thailand. Of course with Thailand's ISPs having bandwidth issues not only to the US and Europe but also outside Thailand we would need a DNS server located in Thailand.

And even then it should not simply be a replication of Google's public DNS but would have to respect the location.

openDNS does NOT have any servers in South East Asia according to their website. Here is openDNS' standard reply to the question about a server in SEA:

we're constantly evaluating new locations to deploy our service. Asia is on our road map but it's a different beast altogether than Europe or the North & South American continents.

most Asian countries operate as independent entities. adding service in Taiwan would not help Hong Kong users. adding service in Japan would be limited to Japan and not impact Korea and vice versa, though i agree both are major markets. Mainland China connectivity is even more restrictive. adding service to Australia would have only a limited impact on the rest of SE Asia.

there are exceptions to my examples, but politics and logistics make it difficult to select where best to roll out new locations to benefit the most users. we are certainly using our statistics, research, and other metrics to help determine this.

When I think about it I doubt that Google has a server in Thailand, or that Thailand would allow Google to have a DNS server in Thailand :)

Could you repeat your test with GoogleDNS?

welo

Edited by welo
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welo Gold Member

welo

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Seems Google's name server is located in Malaysia.

here the results fom my nslookup session, querying several DNS servers for mlone.ak.takecdn.com

Company	  DNS Server		 resolved name			   resolved ip				 location of resolved ip
Maxnet	 202.69.137.137	a1479.g.akamai.net		110.164.253.145, 110.164.253.162   Thailand/Bangkok
openDNS	208.67.220.220	a1479.g.akamai.net		72.246.53.64, 72.246.53.9		  US/Ohio
GoogleDNS  8.8.8.8		   a1479.g.akamai.net		203.106.85.177, 203.106.85.51	  Malaysia/Kuala Lumpur
True	   119.46.240.2	  a1479.g.akamai.net		58.97.45.16, 58.97.45.48		   Thailand/Bangkok

Deducting form those results Google might have a DNS server located in Malaysia. (So much about Thailand being the IT hub for SEA).

From my understanding so far I consider using my ISP's DNS as primary server, GoogleDNS as secondary.

welo

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kudroz Silver Member

kudroz

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Without doing the download speed test again, let's just compare Google Public DNS, OpenDNS and my ISP (3BB/maxnet) DNS servers.

Flickr test

Flickr picture hosting domain: l.yimg.com

OpenDNS

Query time: 265ms

Cache server: 98.137.88.35 (United States - 13 hops and 235ms away)

Google Public DNS

Query time: 53ms

Cache server: 216.115.100.103 (United States - 13 hops and 260ms away)

3BB/maxnet DNS

Query time: 26ms

Cache server: 124.108.79.88 (Singapore - 13 hops and 85ms away)

Facebook test

Facebook picture hosting domain: static.ak.fbcdn.net

OpenDNS

Query time: 294ms

Cache server: 72.246.53.64 (United States - 13 hops and 264ms away)

Google Public DNS

Query time: 53ms

Cache server: 203.106.85.136 (Malaysia - 14 hops and 175ms away)

3BB/maxnet DNS

Query time: 26ms

Cache server: 110.164.253.178 (Thailand - 6 hops and 28ms away)

Result

3BB is faster on query time and also beats them all because it directs you to the closest cache server.

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Pib Star Member

Pib

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Speed should not be the only defining factor. My problem with only using my ISP's (JI-NET) DNS server and even when I was with TOT is I could not reach certain web sites...would always get a broken link error. As soon as I switched my DNS server to Google or OpenDNS I could reach the web sites. I would definitely use my ISP's DSN server as the primary "if" it reach all web sites; but it don't. So, I'm willing to give up some milliseconds in speed in order to reach the web site.

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Beggar Silver Member

Beggar

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Using OpenDNS (OpenDNS directs me to US cache server)

http://mlone.ak.takecdn.com/100MB.zip

Average speed: 163.8 KB/s

Elapsed time: 10 minutes 25 seconds

Using 3bb DNS (3bb DNS directs me to Bangkok cache server)

http://mlone.ak.takecdn.com/100MB.zip

Average speed: 499.7 KB/s

Elapsed time: 3 minutes 24 seconds

I tried both - my Maxnet DNS and OpenDNS resetting all DNS buffers of my system between the trials and checking this with wrong DNS numbers. I got the same speed. But it sounds reasonable if the servers would think and give you to closest server location - but for this example it did not work for me. Can anybody else check it too?

But one more question - is the DNS server really able to locate local cache servers and care about them? Is this not the task of the company providing them to redirect you there?

Edited by Beggar
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welo Gold Member

welo

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Wow, impressive find!

I wonder whether the results from your last benchmark (website loading time) is due to difference in DNS lookup performance or due to CDN related issues (meaning the resolved server not being close to Thailand).

I doubt that the first would make such a big difference, but checking the location of the resolved servers on l.yimg.com (GoogleDNS and openDNS both resolving to the US) the latter doesn't seem to apply here either.

I think from all the benchmark results we have so far (namebench, DNS Benchmark, website loading times, CDN related download times) we can conclude that it is NOT recommended to switch to openDNS for performance reasons.

Seems that GoogleDNS might be a better choice for those looking to resolve stability and reliability issues with their ISP's DNS server.

My choice for now is to use my ISP's server as primary DNS and GoogleDNS as secondary. Let's see if the GoogleDNS as backup helps resolve lookup issues (404 not found).

I still wait to test my TOT connection at home. I'm curious if it might be beneficial to switch to maxnet or true DNS instead of using TOT's wacky infrastructure :)

A word on your flickr test.

I am puzzled that GoogleDNS resolved to a server in the states and not to the one in Singapore, like 3BB does. Assuming that the GoogleDNS mirror is located in Malaysia - is the connection Malaysia-US really faster than Malaysia-Singapore?

welo

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welo Gold Member

welo

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But one more question - is the DNS server really able to locate local cache servers and care about them? Is this not the task of the company providing them to redirect you there?

I guess it works since DNS servers delegate name resolving to the DNS server that manages the domain, and then only cache the result for limited time. The DNS server doesn't have to actively manipulate 'local chache servers' just be able to respond to a lookup request depending on the origin of the querying server.

However, I wonder how this can work if the name resolving process involves actually a chain of DNS servers (each delegating to another server until finding one that 'knows' the answer).

welo

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