Hosts file/Edit

The hosts file is a plain text file used to map host names to IP addresses. On Windows, it is located in the C:\Windows\System32\drivers\etc folder.

Note that the "Hosts" file is owned by the "System" account [NT AUTHORITY/SYSTEM] and may only be modified by an administrator.

Preparation
To prepare for this activity:
 * 1) Start Windows.
 * 2) Log in if necessary.

View the hosts file
To view the hosts file:
 * 1) Open the Start menu.
 * 2) In the Run box, type Notepad.exe and press Enter. Note: If you will be editing the hosts file in the next activity, you must right-click on Notepad and Run as administrator rather than press Enter.
 * 3) In Notepad, select File then Open.
 * 4) Navigate to C:\Windows\System32\drivers\etc.
 * 5) Change the file type to open from Text Documents (*.txt) to All Files (*.*).
 * 6) Open the hosts file.
 * 7) Read the comments in the host file.  The comments begin with a # character.
 * 8) Observe the host records stored in the file.  At a minimum you should find a record for 127.0.0.1 localhost.

Edit the hosts file
To edit the hosts file:
 * 1) Change the line 127.0.0.1 localhost to 127.0.0.1 localhost me.
 * 2) In Notepad, select File then Save to save the file.
 * 3)  Open a command prompt.
 * 4) Type ping me and press Enter.
 * 5) Observe the results.  The ping should be successful, because the name me is now defined as an alias for the loopback address 127.0.0.1.
 * 6) In Notepad, remove me from the line 127.0.0.1 localhost and then save the hosts file.
 * 7) In the command prompt, type ping me and press Enter.
 * 8) Observe the results.  The ping should fail, because the name me is no longer defined as an alias for the loopback address.
 * 9) In Notepad, add a line of 8.8.8.8 googledns and then save the hosts file.
 * 10) In the command prompt, type ping googledns and press Enter.
 * 11) Observe the results.  The ping should be successful, because the name googledns is now defined as an alias for 8.8.8.8.
 * 12) In Notepad, remove the line of 8.8.8.8 googledns and then save the hosts file.
 * 13) In the command prompt, type ping googledns and press Enter.
 * 14) Observe the results.  The ping should fail, because the name googledns is no longer defined as an alias for 8.8.8.8.
 * 15) Close the command prompt and close Notepad to complete this activity.

Readings

 * Wikipedia: hosts file
 * Wikipedia: Internet Protocol
 * Wikipedia: Domain Name System