Saturday, March 20, 2021

Help - Ping request could not find host ... DNS problem

 You may have seen this message before:

Ping request could not find host www.cnn.com. Please check the name and try again.

There could be many things that can go wrong with the networking that caused this. Ultimately it is very likely the DNS that is the problem.

Firstly, let's simply go through a few troubleshooting options - just to rule out it is not because of the them. Do one step at a time, check the WiFi and if it works, don't need to progress to the next step.

1. For older laptops, believe it or not, there is actually a slider switch to click the WiFi on or off. Check this if you have it.

2. On Windows, on the TaskBar, ensure that the Wifi (not any particular Wifi network yet) itself is turn on. The WiFi can be either On or Off or Flight Mode or something else.

3. Check that the Wifi is connected to a particular WiFi network. Make sure it says Connected and Secured. And there is no yellow exclamation mark.

4. Open up CMD command terminal, type:

ipconfig  /release 

ipconfig /renew

ipconfig /flushdns

5. Reboot the computer.

If all else does not work, it is now time to suspect the DNS.

The DNS, in layman's term (you can Google for the exact definition), is directory service that lookup the URL you type and translate to an IP address. Its like a Post Office that receives an address and then go to that address. Our computer need to have the address of the DNS server itself - eg. we need the POST OFFICE's address, so that we can give them our letter.

The so somehow, our computer needs to know which DNS IP address to use. Most of the time, this is hidden from the user, that is why most computer user don't have to deal with it and so don't understand it. It can be automatically set on the modem or router, and also optionally automatically set on the Windows network settings.

So why should there be a problem when the DNS working nicely behind the scenes one day, then the internet is not working the next day? There could be many answers, but a recent experience has shown that some software, including VPN software can go it to the network settings and change the DNS address.

Hence one more solution to above error message is to change the DNS address on the Windows networking level. Whichever Windows version you have, 

- find your own way to the 'Network Connections' page or 'Change Adapter Settings' and you can see a page with a list of your network (ethernet, Wifi, VPN) adapters. 

- Right click on the Wifi adapter, if you are using the Wifi adapter.

- Choose 'Internet Protocol Version 4', and click on the Properties

- Go to the section called 'Use the following DNS server addresses', and add 'Preferred DNS' and 'Alternative DNS'


Some of the free DNS addresses are:

Quad9 - known for security

9.9.9.9, 149.112.112.112 (Secured)

9.9.9.10, 149.112.112.10 (Unsecured)

Google - you know them

8.8.8.8, 8.8.4.4

Cloudfare - known for speed

1.1.1.2, 1.0.0.2

OpenDNS - mature and known for security, 

208.67.222.222, 208.67.220.220

CleanBrowsing - known for parental filtering

185.228.168.168, 185.228.169.168