Editing HOSTS File

Table of Contents

  1. Windows 7, 8, 10
  2. Windows Vista
  3. Windows NT/2000/XP
  4. Linux
  5. Mac OS X 10.0 - 10.1.5
  6. Mac OS X 10.6 - 10.1.8

Editing your computer's HOSTS file will allow you to test your domain against a different server to what the live DNS would normally use. This is commonly used for testing a site prior to making any public DNS changes (ie. during a migration).

When editing the HOSTS file, you add two pieces of information, the target IP address and the domain name (bear in mind that www.example.com is not the same as example.com - these are two different entities as far as DNS is concerned).

So if you wanted to override the DNS for www.example.com to point to 127.0.0.1, you would add the following to your HOSTS file,

127.0.0.1 www.example.com

If you wanted to cover both example.com and www.example.com, you would add the following,

127.0.0.1 www.example.com
127.0.0.1 example.com

Windows 7, 8, 10

Windows 7, 8, 10 use User Account Control (UAC) so Notepad must be run as Administrator.

  1. Click Start
  2. Type notepad, right click Notepad and select Run as administrator
  3. Click Continue on the "Windows needs your permission" UAC window.
  4. When Notepad opens Click File -> Open
  5. In the filename field type C:\Windows\System32\Drivers\etc\hosts
  6. Click Open

Windows Vista

Windows Vista uses User Account Control (UAC) so Notepad must be run as Administrator.

  1. Click Start -> All Programs -> Accessories
  2. Right click Notepad and select Run as administrator
  3. Click Continue on the "Windows needs your permission" UAC window.
  4. When Notepad opens Click File -> Open
  5. In the filename field type C:\Windows\System32\Drivers\etc\hosts
  6. Click Open

Windows NT/2000/XP

  1. Click Start -> All Programs -> Accessories -> Notepad
  2. Click File -> Open
  3. In the filename field type C:\Windows\System32\Drivers\etc\hosts
  4. Click Open

Linux

  1. Open a terminal window
  2. Type sudo nano /etc/hosts (you can substitute any text editor)
  3. Enter your password

Mac OS X 10.0 - 10.1.5

  1. Open /Applications/Utilities/NetInfo Manager.
  2. To allow editing the NetInfo database, click the padlock in the lower left corner of the window.
  3. Enter your Admin password and click OK
  4. In the second column of the browser view, select the node named "machines." You will see entries for -DHCP-, broadcasthost, and localhost in the third column.
  5. The quickest way to create a new entry is to duplicate an existing one. So select the "localhost" item in the third column.
  6. Choose Duplicate from the Edit menu. A confirmation alert appears.
  7. Click Duplicate. A new entry called "localhost copy" appears, and its properties are shown below the browser view.
  8. Double-click the value of the ip_address property and enter the IP address of the other computer.
  9. Double-click the value of the name property and enter the hostname you want for the other computer.
  10. Click the serves property and choose Delete from the Edit menu.
  11. Choose Save from the File menu. A confirmation alert appears.
  12. Click Update this copy.
  13. Repeat steps 6 through 12 for each additional host entry you wish to add.
  14. Choose Quit from the NetInfo Manager menu. You do not need to restart the computer.

Mac OS X 10.6 - 10.1.8

  1. Open Applications > Utilities > Terminal.

  2. Open the hosts file by typing the following in the Terminal window:

    sudo nano /private/etc/hosts

    Type your user password when prompted

  3. Edit the Host File,The hosts file contains some comments (lines starting with the # symbol), as well as some default hostname mappings (e.g. 127.0.0.1 – local host). Append your new mappings underneath the default ones.
  4. Save the Host File, When done editing the hosts file, press Control+x to save the file.

  5. Make your changes take effect by flushing the DNS cache with the following command:

    dscacheutil -flushcache
  6. New mappings should now take effect.

No related posts.