- From: David Woolley <david@djwhome.demon.co.uk>
- Date: Tue, 14 Sep 2004 07:30:50 +0100 (BST)
- To: www-style@w3.org
> > > > In general, that is not true, as browsers will forward the URI to > > a proxy and only the last proxy in the chain need actually resolve the > > address. > > Would you be so kind as to provide an example of this for my humble > enlightenment? It's not uncommon for a big commercial site to have multiple domain names mapped to the same site, in order to catch different guesses as to the site name. If they then link to the canonical name, rather than redirecting, you will have multiple domain names that are internal relative to the site. Most people with an efficiently configured browser will have a proxy configured. Proxies are used by businesses to control access to non-intranet sites, but their primary benefit is that they can cache web pages and therefore improve responsiveness (current authoring practices tend to frustrate caching for HTML, but it often still works for images). If you have caching, the browser always makes the HTTP connection to the same machine and passes the whole URL forward. Proxies can form networks, e.g. the proxy in my office uses the ISP's proxy as a second level proxy, and the ISP's proxy almost certainly uses more sophisticated caching schemes that attempt to find the page in a number of peer proxies. Only when you get a proxy that connects to the real web server is it necessary to resolve the domain name and be able to discover that two domain name parts refer to the same machine. (However, resolving to the same machine name doesn't mean that the sites are related in ownership, as most web hosting services operate multiple virtual domains on the same machine, relying on the domain name being passed forward untranslated, to be used as a tag to select the actual site, and very small businesses are likely to have their main content in visible subdirectories of a generic web hosting domain name (often using hacks with frames to try and hide this from GUI browser users). Also, smaller businesses often try to pretend that a credit card payment processing site is part of their site, even though the domain name is different - this actually compromises SSL authentication, but is very common.)
Received on Tuesday, 14 September 2004 06:32:35 UTC