How Fast Is Your ISP’s DNS Server; Compare with Speed of OpenDNS
OpenDNS speeds up your web surfing because their DNS servers have a large cache and hence can resolve web domains into IP addresses much faster than your local ISP.
But how do you confirm if the DNS Server speed of your local ISP is slower than that of OpenDNS (or vice-versa) ? Simple - use some DOS commands.
Step 1: Open Command Prompt (Start -> Run, Type cmd and press Enter).
Step 2: Type prompt $t - That changes the DOS prompt to the current time, we will need this to calculate the time it takes to execute any DOS command.
Step 3: Now run the following command where 208.67.222.222 is the standard IP address of OpenDNS server.
nslookup www.google.com 208.67.222.222
You can find the time OpenDNS takes to resolved the address by calculating the difference between the two timestamps.
Step 4: Run the same command again but replacing it with the IP Address of your local ISP’s DNS server - in my case, it is 125.22.47.125 (Airtel).
nslookup www.google.com 125.22.47.125
As you can see, the DNS server of the local ISP (Airtel) was slightly faster than OpenDNS in resolving the IP address of www.google.com - something good to know but the difference is insignificant and there are plenty of good reasons to continue using OpenDNS.
Update: You can execute all these commands in a batch file for more accurate results.
ver | time
nslookup www.google.com 208.67.222.222
ver | time
nslookup www.google.com 125.22.47.125
ver | time
This is based on a comment from Resolver - "I found that my ISP’s DNS server is much faster than OpenDNS… because at the moment there are only OpenDNS Server for Europe in London. I’ll wait until OpenDNS Server are in Germany."
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In your example, the times are in HH:MM:SS.SS, so the differences are in seconds. That makes youre differences roughly 10 seconds and 4 seconds. This isn’t an accurate test though since the first prompt of each test was displayed before you even typed the commands, not as the command was executed.
To make this a little more accurate, you could just created a basic batch file with the two nslookup commands, then execute the batch (leaving echo on). It’s output for you test would look more like this:
8:51:01.02dnstest
8:51:03.52nslookup http://www.google.com 208.67.222.222
Server: resolver1.opendns.com
Address: 208.67.222.222:53
Non-authoritative answer:
Name: http://www.google.com.cdc.nicusa.com
Address: 208.67.217.130
8:51:03.63nslookup http://www.google.com 125.22.47.125
Server: AES-Static-125.47.22.125.airtel.in
Address: 125.22.47.125:53
Non-authoritative answer:
Name: http://www.l.google.com
Addresses: 209.85.175.104, 209.85.175.99, 209.85.175.147
Aliases: http://www.google.com
8:51:07.34
In that example, 8:51:01.02 was the time that my initial prompt was displayed. 8:51:03.52 was when the query against OpenDNS started. It then finished and executed the command against your DNS server at 8:51:03.63. The second lookup finished and the batch file was complete at the time of the final prompt, 8:51:07.34. Computing that, we get:
OpenDNS: .11 seconds / 110ms
Airtel: 3.71 seconds / 3710ms
Actually, I also have Airtel as my local ISP, and I get different results. Also, in my experience Google is the worst test case for tests like this (as most places at least Google will always be cached).
I tested various sites with this method (msdn.com, yahoo.com, etc.); in some cases OpenDNS was better, and in others, Airtel.
I like to use OpenDNS also for the fact that I don’t have to worry about the DNS wherever I go. I don’t ever change my DNS.
how is the difference calculated here? is it not the difference between the time last time enter was pressed and when the command was executed?
Amit, either its a misunderstanding on my part of its an error in your statement.
Lemme explain -
1. When you type prompt $t and the the prompt which appears, it shows the time of the appearnace - now to that when you type the command and execute it, there can be a huge time difference based on when you executed and when the initial prompt had come.
Lemme just explain with what you did and where your assertion seems wrong -
1. 17:45:49.62 is the time when the prompt $t executed and appeared and 17:45:59.43 is when the nslookup got completed and time prompt appeared again.
First error - its 17 hrs, 45 minutes, 49.62 seconds. Now, when you executed prompt $t and lets say leave it for a minute or so and execute the nslookup - it’ll show a time difference of 1 minute. You have wrongly asserted it to be 10ms seeing digits 49 and 59 which are actually representing 10 seconds difference which could be time taken to type the entire nslookup command including execution.
Second case you found it to be 4 and you said 4ns - Its kinda misleading(milli to nano) when it is all dependednt on how soon you entered the two commands and pressed the “Return” key.
Am using the upper arrow key to get the previous command and pressing “return” - well, Airtel seems faster for sure as I see a 2 second vs <1second execution time difference. Actual is what the script may give :)
Buts its definitely not the ‘ms’ and ‘ns’ numbers you gave.
Thanks
I think it’ll be perfect if these commands are written in a script and executed - not sure if it’ll be right even then.
I hope you got my point.
Else, feel free to write back :)
Just use dig which is much better at showing timing information.
Does this really work? My DOS prompt shows time in hh:mm:ss.ss format. Assuming the same format applies in the example then it took 10 seconds for OpenDNS and 4 seconds for Airtel. I think this is because the time includes the time to type the command as well as execute the command.
Thanks for taking a look at OpenDNS.
I’d point out that the benefits of OpenDNS’s huge caches are more notable when checking any domain that is not the world’s most popular search engine. ;-) google.com is likely to be in any/all caches, no matter what DNS you’re using. Stray beyond the obvious, and the benefits of OpenDNS’s huge caches start to stack up.
Also, consider the reliability of a zero-downtime, globally-deployed, anycast network.
Just saying…
John Roberts
OpenDNS
Amit, I just posted a (what I believe) comprehensive test on OpenDNS versus Airtel.
http://blog.gadodia.net/opendns-performance-in-india/
If you want, you can point your readers to that.
Cheers.
Dear Mr.Amit,
The Time difference what we see is actually the time taken for us to Type
Only if you run a batch command you will know the actual time
Regards
Bruno