Networking – Better to block a host to 0.0.0.0 than to 127.0.0.1

dnshosts-filenetworking

I have a few hosts that I would like to block in my /etc/hosts file. For that I need to define a bogus IP address that the DNS queries get resolved to.

Most of the tutorials I saw so far all mention 127.0.0.1 as the solution to that. But I was wondering if there is maybe a better or other address, that might already discard the connection earlier.

So I was thinking of using 0.0.0.0 in my hosts-file. Do you think this would work the same like using 127.0.0.1 to block certain hosts?

Best Answer

On Windows there is a difference: packets sent to 127.0.0.1 will end up bombarding whatever server you have running on your computer (and you may be running a server without knowing it), whereas trying to send packets 0.0.0.0 will immediately return with error code 1214 (ERROR_INVALID_NETNAME).

TL;DR: Use 0.0.0.0

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Windows – How to Add Localhost Entry with Port Number to Hosts File

Kamyar, Sadly, the hosts file only associates a name to an IP address. Adding a port would make the syntax invalid.

Check out Windows HOSTS file

My host file is not working on Windows 10

Just changing the hosts file is not enough. You also need to flush your DNS cache.

Open a command prompt and type:

ipconfig /flushdns

Now, test if it works by pinging one of the domains, preferably one you changed recently:

ping www.website2.com

and see if it returns the 127.0.0.1

If the ping does not work, then it is likely that the permissions on the hostfile are incorrect. Incorrect permissions on the hostfile may cause an arbitrary lock on the hostsfile which prevents windows from properly read it and populating the dns cache. Fix the permissions on the hostfile then perform an ipconfig /flushdns once more.

If the ping works, but the website does not load correctly, then the website is still loading from cache. Clear your browsercache to fix the issue.

Best Answer

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Windows – How to Add Localhost Entry with Port Number to Hosts File

My host file is not working on Windows 10

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