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Is my router acting as a DNS server?

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So when I access the command prompt and enter ipconfig/all one of the entries listed is “DNS Server” and IP address 192.168.x.x. I understand that my wireless router is my LAN’s default gateway and acts as the DHCP server – but DNS server? My operating system is Windows 7 Home Premium.

Yes, your router could in fact be acting as a DNS server. There are various reasons that it might be doing that, most of them related to speed.

First, let’s quickly review what DNS actually is.

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DNS

I’m sure by now you realize that every machine that’s connected directly to the internet is identified by a number called an IP or Internet Protocol address. An example might be 67.225.235.59.

Now, that’s hard to remember. Humans prefer to remember things by name, like AskLeo.com. DNS is a service that computers use to ask the question, “What is the IP address of AskLeo.com?”, and get an answer.

Traditionally, the DNS servers that handle these requests are provided by your internet service provider.

There are also third party DNS services. One is called OpenDNS, and I think Google has a DNS service that you can use instead of your ISP’s for various reasons (again, most of which relate to speed). OpenDNS also offers a filter that you can apply to prevent people from going to known bad locations, and I think there’s a porn filter that’s available as well.

DNS requests

So, that DNS request that’s being made by your computer normally goes out over your internet connection to your ISP’s DNS servers. And then the response comes back, for every domain name you access; be it mail, websites, the ads appearing on those websites, internal things used by Windows, and much, much more.

There are lots of different internet domain names that you end up accessing these days by simply using your computer over the course of a day. So, given that your DNS server is used so heavily, it’s something we can try to optimize for speed.

Speeding up DNS

That’s where your router comes in. Many routers will actually set themselves up to be your DNS server. When you make a request for something that the router’s DNS server has never heard of before, it asks your ISP’s DNS server for the answer. In other words, the request gets passed upstream.

Router BacksideThe important thing is that when the answer comes back, the router remembers it.

For example, the first time you go to AskLeo.com, your router’s never heard of it, so it asks your ISP’s DNS servers, “What’s the IP address for AskLeo.com?” The DNS server responds with 67.225.235.59. The router remembers that answer and then of course, it passes the response back on to your computer.

The next time you ask for the IP address of AskLeo.com, the router doesn’t have to ask anybody else. It just knows right then and there, which means it doesn’t actually have to pass that request across your internet connection and get the response back again over your internet connection. It all happens locally, and it typically happens much faster than if you were relying only on your ISP’s DNS server.

Not all routers do this, and some don’t act as DNS servers by default, but can be set up to do so. Sometimes your ISP will configure things completely differently from what I’ve described. To be honest, whether or not your router is acting as a DNS server will not make a huge difference in your internet speed, but it can make a small one.

If you’re not sure and if things are working, I typically recommend you leave well enough alone.

14 comments on “Is my router acting as a DNS server?”

  1. My router is a DNS server by default; WRT160N. I set up openDNS servers as DNS1, 2, 3 but as you said above ipconfig lists my routers IP as DNS1. Is it using it’s own DNS servers or the ones I put in?

    • Set up filtering on DNS then try to access filter sites. If open DNS is in control you should see a open DNS screen listing blocked site and suggest contacting your network administrator.

  2. Leo,

    I had kind of figured out that the router acts as the DNS server for my IP phone before reading this page, but it was great to hear such a thoughtful explanation. There is an art to explaining what others take for granted. Still I have one nagging question. In my IP phone configuration (not the router), I set the primary DNS server to my router address, the secondary to 0.0.0.0. But it wants a “DNS Domain” described as “Enter the phone’s Domain Name System (DNS).” I have no idea what to enter into this parameter or how the value is used. Can you please help.

    Luther

  3. I’m looking for a current router that has DNS and DHCP services built in. It’s easy to find DHCP but it seems that the only way to get DNS on a consumer router is to overwrite the firmware with customer firmware such as Tomato, DD-WRT, etc.

  4. Hello
    I have a question….few days ago i was at my friend’s house and i connected to his router, now i am on my own router at home. When i open cmd and powershell and check some of displayed dns there are some sites i haven’t been to? Does that have to do something with connecting with my friend’s router? Do i see his browsing or?

  5. My computer manually configured to use opendns works fine. I’m trying to use the service that does not require the dashboard just phishing and botnet protection on my router and put the computer back on obtain dns auto. Opendns does not work using the router, I get the oops! page. I’m not concerned about the dashboard and ddns at this time. I’ve tried flushing dns, brower cache, rebooting rooter and computer…I have tomato firmware and have vlans setup. I can access the internet from all of them with no problem with the computer set on obtain ip address auto and manually set and the same for dns. If it works on the computer why not on the router? Thanks in advance.

  6. I have a question
    If i’ve been connected to my friends router for one day, then i returned to my own router the other day, can i see all the ip adresses of sites she visited from my own router because i was connected to hers? or thats not possible?

    • You would only be able to see any traffic which passes through own router if your router logs visited websites. Having accessed the internet or her LAN with your computer would not give you access to anything on her network or vice versa.

  7. So we have Verizon Gig service. I get that the Verizon Router should be acting as the primary DNS server and forwarding on what it doesn’t know that which has expired past its TTL, however, our Router the GS1100, while also acting as our DHCP Server, as well as holding the local ARP table for all the local intranet devices that are connected to it, however, it does NOT respond if you set it as the primary DNS. This is actually very frustrating. I have many devices on the local network that are given their FQDN and IP addr from the router, as they all have the router set as their default gateway. but if I set the same IP as the primary DNS I wind up getting an unauthoritative answer from the secondary DNS server which happens to be one of Versions DNS servers which is extremely slow, and knows nothing of the local hosts. If anyone knows a way to correct this other then putting in a local DNS server which if I could find one that works in Windows 10 I would do in a second. I would really prefer that the router handle the primary / local DNS since all the data is already being stored, but I can’t find anyway of accessing it.

    • To be clear, you’re saying that the Verizon router is not properly responding as a DNS server? I’d a) scour its configuration if you have access to it, b) contact Verizon — though you may need to insist on a second-level technician to get this level of detailed help. Alternately if you can turn OFF DHCP and DNS in the router, you could let it act as nothing more than a gateway, and then add your own router to do the job needed.

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