📖 IT Bible

Unable to Resolve a Hostname or Domain Name

  1. First up, if you are unable to resolve a domain name, ​check that your network connection is actually working.

    • ​You can do a quick check and ping ​a website that you know is available in oldie, ​but goodie is to ping www.google.com.
    • go into my terminal and type ​in ping, www.google.com. Pasted image 20260627204644

  2.  ​Let’s move on to isolating another problem, DNS. ​To verify that your DNS server is giving ​you a correct address for google.com, ​you can use NS lookup. ​

    • Remember that NS lookup gives us ​the name server of a host or domain name.
    • From here, we can rule out if DNS is ​an issue by verifying that ​the hostname points to a name server. Pasted image 20260627204740
    •  ​If we copy the IP address or ​the results and paste it into the web browser, ​it should resolve the website name if ​DNS is working. Pasted image 20260627204906 Pasted image 20260627204933
    • it’s not working, which means DNS settings aren’t working correctly
    •  ​Let’s look at my ping results again. ​I’m going to go ahead to my terminal ​and ping www.google.com.  Pasted image 20260627205057
    • ​I see that it checks ​an IP address different from what I have here. ​If I go to this IP address, ​it doesn’t take me anywhere. ​I’m going to take this IP address, copy this. Pasted image 20260627205153 Pasted image 20260627205215
    • Remember that when a DNS query is performed, ​your computer first checks host file. ​Now, if I access my host file here, ​I can see that I have an entry for www.google.com, ​and it points to a fake IP address. Pasted image 20260627205402
    •  ​If I remove this line right here where ​it says 127.1.1.3, ​and save that configuration file, ​and then restart my browser. ​If I type in www.google.com, here we go. ​We’re there and the correct DNS setting ​should be applied to www.google.com Pasted image 20260627205509