View source for Debian: Edit the Hosts File

All major operating systems have a hosts file to translate hostnames to IP addresses. The hosts file has priority over DNS lookups. Whenever you open a website by typing its domain name, your system will read through the hosts file to check for the corresponding IP and then open it. The hosts file is a simple text file located in the /etc folder of your Debian system, the full path is '''''/etc/hosts'''''.



From what we mentioned, you might expect this file to have a very long list of IPs and corresponding hostnames; but that is not true. The hosts file only contains several lines;

* The first part, by default, contains hostnames and IP addresses of your localhost and machine. This is the part you will usually modify to make the desired changes.
* The second part has information about IPv6-capable hosts; you will hardly be editing these lines.

Whenever you type an address, your system will check the hosts file for its presence; if it is present, you will be directed to the corresponding IP. If the hostname is not defined in the hosts file, your system will check the DNS server of your internet to look up for the corresponding IP and redirect you accordingly.

== Why Edit the Hosts File? ==
By editing the hosts files, you can achieve the following and much more:

* Block a website
* Handle an attack or resolve a prank
* Create an alias for locations on your local server
* Override addresses that your DNS server provides
* Control access to network trafficIn this article, we will use the Nano editor to edit the hosts file. Please type the following command to open the hosts file:
 $ sudo nano /etc/hosts
Or
 $ sudo gedit /etc/hosts



As mentioned, we will edit the first part of the hosts file where IP addresses and hostnames are defined. We will explain the following two ways in which you can make use of the hosts file:

* Block a website
* Access Remote Computer Through an Alias

== Block a Website using the /etc/hosts file ==
You can block a website by redirecting it to the IP of your localhost or the default route.

For example, if we want to block google.com, we can add the following text to our file:
 127.0.0.1 www.google.com
Now when we open the google website, our system will take the IP of our localhost (127.0.0.1) from the hosts file and redirect us to that instead of the google IP from our DNS server.

OR
 0.0.0.0 www.google.com
Now when we open the google website, our system will take the IP of the default route (0.0.0.0) from the hosts file and redirect us to that instead of the google IP from our DNS server.

This is how the edited file will look like. Please save the changes by hitting ctrl+X and entering y on the filename prompt.


Please note that we have defined the complete address www.google.com instead of just the hostname google.com in the hosts file because modern browsers sometimes circumvent the block if we only define the latter.

== Access Remote Computer Through an Alias ==
Suppose we have a server located on a local network that we want to access. We usually have to type the server’s IP to access it unless it has been defined on our local DNS. One way to avoid typing the IP again and again is to assign an alias to the server in the hosts file as follows:
 192.168.1.10 myserver
The IP corresponds to the location of the server we want to access, and myserver is the new alias we want to use.


When we save the file and type myserver in the address bar, we will be redirected to our remote server.

We have learned that by making very simple changes to the hosts file, we can customize and thus redirect the network traffic according to our needs. We can also eliminate a network attack or prank by restoring the hosts file to its default.

== Source ==

* [https://vitux.com/hosts_file_debian/ vitux.com]

[[Category:Linux]]
[[Category:Debian]]