Hostname redirection using Hosts file

Question

We can use C:\WINDOWS\system32\drivers\etc\hosts file to map hostname with IP addresses like this

127.0.0.1 localhost

But is it possible to assign one hostname to another like this?

localhost a_new_host_name

Solution 1

From wikipedia :

The hosts file contains lines of text consisting of an IP address and one or more hostnames, each field separated by white space (blank or tabulation characters). Comment lines may be included; they are indicated by a hash character (#) in the first position of such lines. For example,

#This is an example of the hosts file
127.0.0.1  localhost loopback

Solution 2

You could put in the hosts file:

a_new_host_ip_addr localhost 

Beyond that, I think you would need to set up a local (or nearby) DNS server with CNAME entries to map localhost to some other host (and you'd have to remove 'localhost' from the hosts file for this to work).

Solution 3

You may have got the impression that some kind of 'redirection' is possible from things like

127.0.0.1    ads.stackoverflow.com

in your hosts file. Purely as an example, you understand. This does not conflict with the usual definition of localhost elsewhere in the same hosts file.

The Internet has a number of sample hosts file which ensure that unwanted images don't appear on your screen.

Comments

[bdhar]

Just tried. It does not work. But is there an alternate way to achieve this?

[CivMeierFan]

I think setting up a local DNS server is required, which is not as trivial.

[Arjan]

I am not sure if this is a good advice. Why would one ever make localhost point to a different IP address?

[Arjan]

One could also use 74.125.79.18 superuser.com to make the domain name superuser.com erroneously point to a (current) IP address of the Google servers. However, a browser will send the original hostname in the HTTP request. Many shared web servers host multiple domains on a single IP address (like 74.125.79.18 is google.com but also gmail.com), and then only accept known host names or default to some specific site when an unknown name is requested. So, one cannot really use a hosts file for reliable "redirection", though one can indeed redirect to "nothing" (like in the answer above).

[Mnebuerquo]

Attackers sometimes try to hijack dns using this method. It doesn't get you much when you make it point to a google server, but if you are the attacker you can make it point to your own server where you spoof their bank's login page or whatever.