How to change the DNS settings on a Cisco 870 Series router

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Setup Router Staff
(Last Updated: ) | Reading Time: 4 minutes

This page shows how to change the DNS settings on the Cisco 870 Series router.

Other Cisco 870 Series Guides

This is the dns guide for the Cisco 870 Series.We also have the following guides for the same router:

What is the DNS setting on a Router

When you connect a router to the Internet it gets a few settings from your ISP automatically. One of the settings that the ISP sets in your router is the DNS setting. DNS stands for Domain Name System and it is used to convert Internet names into actual IP addresses. For instance, when you go to "", your are really connecting to an IP address that is mapped through DNS to a number such as:

This mapping happens automatically every time you visit any page on the Internet.

Why Change Your Router's DNS Setting

Some ISPs choose to abuse the DNS system and map unknown names to servers that they control. This can be done in a way that you don't know it is happening since your router is getting its DNS settings from your ISP. For instance, if you have one of these ISPs who is hijacking your DNS, and you try to surf the web to "" and "" does not exist, you might get a page back from your ISP with local advertisements on it.

By changing your DNS setting in your router you will effectively change the DNS setting for every computer on your network. This is because when a device is connected to your network your router automatically hands out its own DNS settings to that device. This way you can protect your entire network from ISP hijacking with just one setting.

What Should I Change My DNS To

There are 2 really great DNS servers on the Internet that you can choose from right now: Google Public DNS and OpenDNS. If you are not sure which one to pick then just use Google Public DNS.

When you change the DNS settings in your router, you usually have to enter a Primary and a Secondary setting. The secondary is only used if the primary can not be located. Here are common settings:

If you want to use Google Public DNS, use the following settings:

If you want to use OpenDNS, use the following settings:

Login To The Cisco 870 Series

To get started configuring the Cisco 870 Series DNS page you need to login to your router. If you are already logged in you can skip this step.

To login to the Cisco 870 Series, follow our Cisco 870 Series Login Guide.

Change the DNS settings on a Cisco 870 Series

If you followed our login guide above then you should see this screen.

router status mac address internet IP
This is the status page from your Cisco router.

From the Status page of the Cisco 870-Series you click the choice in the left side bar labeled Advanced, then WAN Port.

Configure the DNS section of your Cisco 870 Series

router dns setting
This is the dns page from your Cisco router.

You should now be on the WAN Port Configuration page. Scroll down and tick the radio button labeled Set DNS Manually.

You can now set your DNS Server. In the box labeled DNS 1 enter the primary address of the DNS server you have decided to use.

Under that is the DNS 2 box, enter the secondary address of that same DNS server.

You don't need to enter anything in the DNS 3 box, you won't need it.

Finally, click Apply Changes at the bottom of the page.

That's it, you did it!

Possible Problems when Changing your DNS settings

Most devices on your network will not begin using the new DNS settings until they have been rebooted. After rebooting a device you can go to it's network settings and verify that it is using the DNS servers that you specified.

Other Cisco 870 Series Info

Don't forget about our other Cisco 870 Series info that you might be interested in.

This is the dns guide for the Cisco 870 Series.We also have the following guides for the same router: