How can I direct traffic to Subdomains in /etc/hosts?

Question

I tried to put the line to /etc/hosts:

IP math.com mathworld.com

where IP was supposed to be the IP of http://mathworld.wolfram.com/classroom/. I pinged the site, and I realised that I must direct traffic with some other tools:

ping mathworld.wolfram.com/

ping: cannot resolve mathworld.wolfram.com/: Unknown host

So the question arises:

How can I direct traffic to subdomains, similar to the above subdomain?

Answer 1

Your ping failed because you had a trailing / on the hostname, which isn't valid.

Are you trying to create your own local alias URL that drops you into the right part of that specific third-party URL?

That can't work on its own, because:

1. the third party site will see your hostname alias in the Host: HTTP headers, which it won't recognise
2. it won't drop you into the right subdirectory of their server

To make this work you'd need to point that local alias towards a web server that you control, and then have that server issue an HTTP redirect to the real site.

Answer 2

You seem to be confused about networking terminology.

http://mathworld.wolfram.com/classroom/ is a URL, not a domain name. It has no IP address. mathworld.wolfram.com is a domain name and has an IP address.

Also, mathworld.wolfram.com is a subdomain of wolfram.com which is a subdomain of the com top level domain.

mathworld.wolfram.com is not a subdomain of mathworld.com

The /etc/hosts is not powerful enough to map all subdomains of a domain to the same place. You will need to type them all out, or go into proper DNS server configuration (such as named.conf).