A DNS filter is similar to the  hosts file approach  of blocking websites, but we're basically using someone else's managed hosts file. Additionally, we can block entire categories of websites without specifying each website we want to block.

When you try to try to load a website a DNS filter will check the website hostname against a massive list of categorized hostnames. If the requested page is in a category you want to block (like adult content), the DNS filter blocks the webpage from loading.

In this tutorial we will set up the free OpenDNS filtering service. However, we don't recommend using OpenDNS permanently. It's potentially the least effective content filter. 

Read our DNS Filtering comparison here . 

It's simply the easiest one to setup, so we'll use it for the purposes of showing you how to configure content filtering on a home network.

Quick Setup with Family Shield

The fastest way to get started with content filtering is to use the pre-configured Family Shield that doesn't require any customization. Learn how to quickly test and configure the FamilyShield DNS service on a computer & home network:

Use this approach if you want to:

• Quickly start filtering adult content with almost no setup required.
• Enable DNS filtering on a specific device.
• Use DNS filtering on any network.
• Learn the basics of setting up custom DNS.

IP addresses used in this tutorial

208.67.222.123
208.67.220.123

Switching to OpenDNS Home

In this tutorial we'll expand on the previous Family Shield implementation so that we can customize the filtering and protect our entire home network.

Use this approach if you want to:

• Configure your router to use DNS filtering
• Customize DNS filtering to block specific websites, not just Adult Content categories
• Handle IP address changes that break DNS filtering

In this video:

• Switching from pre-configured DNS to custom DNS.
• Additional troubleshooting and testing.
• Accounting for dynamic IP addresses.

Setup and Test

On your computer (for testing purposes) change your DNS IP addresses to the OpenDNS Home nameservers: 

208.67.222.222
208.67.220.220

1. How to change IPv4 settings on Mac
2. How to change IPv4 settings on Windows

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Create a free OpenDNS home account

In the OpenDNS dashboard, click "Add a network"

OpenDNS will automatically fill your computer's IP address

Click the network you just created to open configuration options

Test that your custom filtering settings work by only filtering by the social media category.

Open an incognito or private browser window and try visiting facebook.com. You should get the following certificate error.

Configure Home Network

• Check the back of your internet router for router login credentials (if you didn't set this up yourself).
• The router is the device that also handles Wifi. Sometimes the router and modem are combined into one device. In other cases, you might use a modem and router seperately
• Try either IP Address in your brower's address bar: 192.168.0.1 or 192.168.1.1

• Find the section where you modify your DNS. You should see the ability to set custom primary and secondary DNS addresses.

• Enter Primary DNS: 208.67.222.222
• Enter Secondary DNS: 208.67.220.220
• Save changes and wait a few minutes for your router to reflect the new configuration.

Flush DNS

Windows

On windows machines, open command prompt. Type "CMD" into your search bar and then open it.

Type `ipconfig /flushdns` then press enter.

Mac

Use finder to open Terminal

Type sudo killall -HUP mDNSResponder and press enter

If prompted for a sudo password, enter your administrator account password (probably the account you login to your mac with)

Testing Open DNS

If you've configured OpenDNS on your home network or on a computer, you can test to see if it's functioning properly by navigating to  welcome.opendns.com .

If everything is working properly you should see the following:

Otherwise, you'll see this page:

Additional Testing

In addition to using the  status page  provided by OpenDNS, you can also test DNS status using the same terminal/command prompt that you use to flush your DNS.

Type the following command with any domain name: nslookup facebook.com

You should see your associated DNS filter's IP address or server name.

• Once you've confirmed that the OpenDNS works when you directly configure it on your computer, reset your computer's DNS settings back to automatically assigned DNS. You need to do this to test your router configuration.
• Update your router configuration to point to OpenDNS instead of FamilyShield (see previous video). Just change the IP addresses from the FamilyShield nameservers to OpenDNS Home nameservers.

Handling Dynamic IP Addresses with IP Updater

For OpenDNS Home, recall that we entered an IP address when configuring OpenDNS Home. If you're like 99% of network configurations, you probably have a dynamic IP address. This means that the IP address you entered previously might change in the future.

OpenDNS provides the ability to synchronize IP address changes automatically so that you don't have to update the IP address manually every time.

• Go to settings > Advanced > Select your device
• Click "Enable dynamic IP update"
• Click apply

• Download and install the  dynamic updater client
• The client is plug-and-play. After the installation finishes, login with your OpenDNS account. Follow this  short tutorial  if you need more help with this part.

The IP address updater should not be used on a computer that uses a work VPN. A work VPN will cause the updater client to send an incorrect IP address update, which will cause your network to stop functioning if you're not on the work VPN.

What happens if your IP Updater stops working?

Your internet will continue to function, but filtering will stop working entirely. This is one of the reasons we don't recommend OpenDNS Home.