I am using Comcast. And my router is set up to acquire DNS server automatically. How can I find out the IP address of the DNS server used by my router? I am using Windows. Is there some Windows command that I can use?

  • If your device also handles DNS it's more than a router. – andol Dec 20 '09 at 20:42

You can do one of two things:

  1. If your router is just passing Comcast's DNS servers then you can issue an ipconfig /all at the command line and it will tell you (Comcast's servers would be 68.xx.xx.xx not 192.168.xx.xx)

  2. If your router is passing itself as the DNS server, then you should be able to go on the router's admin interface status page and see what DNS servers it got from comcast's DHCP server.

  • Thanks! I followed (2) and found the IP through the router's admin interface. – thebat Dec 21 '09 at 6:20
  • If I'm behind a router that acts as a DNS, and then I set my own DNS on my network adapter, does this overwrite the Router? – CMCDragonkai Jun 16 '14 at 5:43

I can't find the link right now but there are DNS-based domains which will accept a query and return the IP address of the requesting DNS server as the "resolved" answer. They won't report all your configured DNS servers but they could be useful when you don't have access to the DNS box.

A web-based page which include this info is http://www.dnsstuff.com/tools/aboutyou/


Running the recently released Namebench will tell you what DNS server you're using and will also tell you if there are faster ones available.

Word of warning it takes a few minutes to run, but the results are enlightening.

  • I tried this. But it says that my DNS server is – thebat Dec 21 '09 at 6:19

You can use the nslookup command to check DNS resolution.
Open a cmd terminal window (Start -> cmd > run). Type:
nslookup www.google.com
The first two lines are the domain server you are using

In my case:
C:> nslookup www.google.com
Server: cns.sanjose.ca.sanfran.comcast.net

my dns is 68.....

  • 2
    This just tells me because we're still behind a router. – CMCDragonkai Jun 16 '14 at 5:46


ipconfig /all

This should list your DNS servers properly. These are the ones used by your computer, passed on to you by your Comcast cable modem / router.

  • 1
    Many SOHO routers don't pass on the upstream DNS servers to their clients via DHCP. – Alnitak Dec 20 '09 at 19:39

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