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< World Wide Web | Knowledge Base | X11 >

In standard web-URI nomenclature, "www"is the usual sub-domain for an HTTP (World Wide Web) server. It is a way of formally delineating the website of a domain from its other functions.

It is a good idea to not have a web server responding directly to queries on a bare domain. I.E. a site should be on www.vistua.com not vistua.com because this leads to semiotic and syntactical ambiguities.

In that example, "vistua" is a domain in the "com" zone. All DNS zones are expressed in increasing priority when read from left to right and administratively each node represents a potential division of management authority. "Com" is technically a "top level domain" of the root zone. "vistua" is a domain in the "com" zone and "www" is a subdomain of the "vistua" domain.

If, therefore, the website was accessed at the URI "http://vistua.com", then what exactly does "vistua.com" refer to? If email addresses exist in the @vistua.com addressing scheme¹ this becomes even more confusing. For conveniences sake² , most web-servers listen to their "bare domain name" and redirect to the www subdomain. For example, if you type "vistua.com" into your browser location bar, you will be automatically redirected to "www.vistua.com"

As a result of this, it is not necessary to type www in most cases. It is particularly important to not use www on sub domains unless the site in question is badly administered³ and fails to respond without the www subdomain. For example, one would not usually type www.mail.vistua.com but would instead enter mail.vistua.com

Notes

¹ In the specific case of the administration of this site's DNS architecture, there are no @mail.vistua.com email addresses bothg because such a long address would be cumbrous and more prone to spelling errors and because the mailserver's actual "Fully Qualified Domain Name" is not mail.vistua.com anyway. "mail.vistua.com" refers to a webserver (technically, its a CNAME but that's an enormously complex topic wildly outside the scope of this document) that provides the web-based groupware mail. Administratively, the reason that there is no "www.mail.vistua.com" is that such a thing is overcomplex to type and that "mail.vistua.com" serves the needed purpose of disassociating the groupware mail from the bare domain and the website (it is served from a different webserver).

² In principle, the server should probably not be doing this. However in practice most users do not type "www" and so may assume that the site is down or nonexistent when the navigation activity appears to fail.

³ Technically, this is arguably formally correct but most definitely constitutes pedantry.

Categories: Internet

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