[Web4lib] name based virtual hosting and ip addresses

[Rob Styles]

John,

What happens when you type the address of a web site into your browser is this:

The browsers asks the underlying operating systems to open a connection to the web server.

The operating system looks up the name it's been given in DNS and (hopefully) receives and IP Address back; it opens a connection to this IP address and hands that back to the browser.

The browser then sends a message down that connection; the message looks like this:

	GET / HTTP/1.1
	Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, */*
	Accept-Language: en-us
	Accept-Encoding: gzip, deflate
	User-Agent: Mozilla/4.0 (compatible; MSIE 5.01; Windows NT)
	Host: hypothetical.ora.com
	Connection: Keep-Alive

Literally like this, it's just plain text. Notice the line that starts "Host: " that's the information the server is using to decide which site to give you. It's probably got a default setup for if that's not there; that's what you'll see if you use the IP address in the browser.

So, because the server expects this information in the header of the request the browser doesn't provide any facility to add it anywhere else (AFAIK). There are some tools and plugins out there that allow you to mess with the headers, but they're probably overkill for what you want.

Now, how to solve your problem. The only reason I can think of for using the IP address in the browser's address bar is because DNS isn't working, so the name doesn't work. If that's the case you can use the fore-runner to DNS, the 'hosts' file. On UNIX or Linux systems this is typically in /etc/hosts (you'll need root access to modify it) and on windows it's in C:\WINDOWS\system32\drivers\etc\hosts. Either way it's a simple text file that you can edit using notepad or vi or any text editor. The file usually has examples in it to show you what to put in, but it's just IP address <tab> hostname. If you're using a proxy server this entry will have to go on the proxy server, not the browsing machine.

The downside to that, of course, is that if the site moves IP address then you will have to know and update your machines manually.

Why do you need to do this?

Rob Styles
Technical Lead, Talis
 

> -----Original Message-----
> From: web4lib-bounces at webjunction.org [mailto:web4lib-
> bounces at webjunction.org] On Behalf Of John Fitzgibbon
> Sent: 15 January 2007 16:40
> To: web4lib at webjunction.org
> Subject: [Web4lib] name based virtual hosting and ip addresses
> 
> Hi,
> 
> I am attempting to access a web site that is served by a web server that
> uses a type of hosting called name-based virtual hosting. The server
> hosts several domains and serves the correct page based on the domain
> name submitted to it. Simply, typing the IP address of the domain in the
> address bar will not work; the domain name must also be submitted to the
> server.
> 
> With such hosting, is it possible to retrieve the web site by typing the
> IP address in the address bar along with additional information? What
> form should this additional information take?
> 
> Regards
> John
> 
> John Fitzgibbon
> 
> p: 00 353 91 562471
> f: 00 353 91 565039
> w: http://www.galwaylibrary.ie
> 
> John Fitzgibbon
> 
> p: 00 353 91 562471
> f: 00 353 91 565039
> w: http://www.galwaylibrary.ie
> 
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