How To Edit, Reset The Windows Hosts File
The question came just up again and I realized that I have never posted a tutorial about editing and reseting the Windows Hosts file. I'd like to take a look at the Host file's functionality first.
The Windows Hosts file can be used to block or redirect hostnames. A hostname is the core part of a web address or local address, for instance ghacks.net or localhost. Each hosts file entry specifies an IP address and a hostname, which basically tells the system that the hostname should be resolved with that IP address.
The DNS server, that is usually queried, is bypassed for all entries in the Hosts file unless hardcoded in the operating system.
Let me give you two examples where this may be beneficial: users could block known advertising companies or spammers by redirecting requests to the local PC. This basically loads nothing when a website tries to load an advertisement, popup or other element.
Another example highlights that the hosts file can be beneficial to web developers. Say you just moved your website to a new server and the IP changed in the process. DNS servers need up to 48 hours to propagate, which means that it is difficult to test the website on the new server after the move if the DNS server is still redirecting the request to the old server.
The web developer could assign the new IP address to the website to avoid the propagation issue. (Please see Work On Websites Before DNS Propagation for a detailed guide on that subject)
It has to be noted that the Hosts file can also be exploited by malicious software, either by redirecting the user from legit sites to questionable ones, or by blocking access to security software that they might need to remove those programs again from the PC.
The location of the Windows Hosts file
The Windows Hosts file is located under the following path:
The %SystemRoot% in the beginning is a variable that is set to the Windows directory. Most Windows users have installed the operating system on c:\windows which would mean that the hosts file can be found under c:\windows\system32\drivers\etc\hosts
It may be necessary to display hidden system folders if Windows Explorer is used to navigate to the folder.
A click on Tools > Folder Options in Windows Explorer and a switch to the View tab opens a configuration menu where hidden folders can be set to be revealed.
If you use Windows 10, select File > Change Folder and Search options instead and switch to the View menu then.
Locate "hide protected operating system files (recommended)" and "hidden files and folders" and make sure that the former is unchecked, and that the latter is set to "Show hidden files, folders and drives". The settings can be easily reversed this way when needed.
The Hosts file itself can be edited with any plain text editor, Notepad for instance which ships with Windows. You should check first if the Hosts file is write protected. This is done by right-clicking the file and selecting properties from the opening context menu.
Look at the attributes section of the General tab. The file is write protected if read-only is checked. If it is, remove the entry. If you keep the read-only setting it is not possible to edit or reset the hosts file.
Remember to set the read-only attribute again once you are finished to prevent third party editing of the hosts file.
The default Windows Hosts file has no active entries. Please note that a line beginning with # is a comment line which will not be executed or processed.
Editing the Windows Hosts file
Take a look at the examples in the comments. The syntax is always the same, first the IP address that you want to redirect the hostname to, then the hostname separated by at least one space.
- To add entries to the hosts file you would enter the IP address first in the next blank line, followed by a space (or by pressing tab) and the hostname (which can be a domain name or localhost).
- To delete Windows Hosts file entries select the whole line and press the delete button on the keyboard. You may also add # in front of any line to make it a comment so that it is not processed but preserved.
- To edit individual entries click in the line of the mapping that you want to edit and make the changes.
- To reset the hosts file simply remove all lines that are not comments. Microsoft has created a Fix-Ii solution to reset the hosts file which can be used instead. Users just have to execute the program once they have downloaded it to the local system. The main benefit is that they do not need to go through the manual process this way.
Please note that you need to save the changes before they become available. In Notepad you would select File > Save from the menu to do that.
And that's how your edit and reset the Windows Hosts file. Please leave any open questions or comments in the comment section below.