Intro to Website Technologies

The purpose of this class is to provide a broad overview of the technical components required to have a website.

Domain Names

Domain names are perhaps the most familiar aspect of websites. Whether it is FreeGeek.org or Linux.com, these are memorable names which we can use to identify the websites found at those locations.

Registration

One 'registers' a domain name, by choosing a registrar, finding an available domain name, and paying an annual fee for that domain name.

Some notable registrars are:

• Enom
• Network Solutions
• GoDaddy

WHOIS

Every domain name must have certain contact information available. This is called the WHOIS registry (or database). It is public information, and many registrars sell 'privacy listing' services to hide your contact info and thus prevent spam.

Top-Level Domains

Top-Level Domains, or TLDs, are the technical term for the ".com" part of a domain name. While the generic TLDs are still available, each country has been assigned a two-letter country code, such as ".us" or ".uk" -- each country controls domains in their TLD, and set prices as they see fit.

IP Addresses & DNS

Perhaps you've heard of an IP Address. Each computer connected to the internet has a unique IP (Internet Protocol) address, much like a phone number. These IP addresses are used to contact a server or other device connected to the internet. Because IP addresses are fairly difficult to remember, we use domain names, and rely upon DNS, or the Domain Name System, to resolve a domain name to an IP address -- much like a phonebook or similar directory.

URL Structure

URLs are not read in a left-to-right fashion, as many might expect -- instead, the domain name is processed first, to determine which server we wish to connect to. Next comes the protocol used to communicate, and the path to a resource we're requesting. Finally, there can also be optional query strings, or anchors.

1. TLD

The TLD is the first part of a domain name to be used. Each country controls the domains within their TLD, so those systems must be contacted to resolve the next step.

1. Domain

The domain name is perhaps the most recognizable part of a URL. Using DNS, the domain name is resolved to an IP address.

1. Subdomain

Next, the subdomain is resolved to yet another IP address.

1. Protocol

Now, with the IP address of the desired server, we must contact that server. The protocol (http://) is how that communication should be conducted. This could be analogous to spoken language.

1. Path

Once a communication protocol has been established, we can make our actual request for a resource on that server. Often, this is an HTML document or at image, but it could be just about anything.

1. Query String

The query string is how we can pass information to the server, to help it respond to our request. Perhaps a webpage will display a certificate; it will need a name to display. By adding a question mark to the end of a URL, and separating each piece of data with an ampersand, we can provide this information, like so; ?first_name=John&last_name=Doe

1. Fragment Identifier

Last, comes the fragment identifier, or more commonly, an anchor. This allows us to point the user to a specific point in a document. One example might be, a long webpage with the contents of a book; there is a table of contents near the start, and clicking on 'Chapter 3' will cause the webpage to scroll down to chapter 3. It is added on to the end of a URL, like this; #chapter3

See Also

• Domain name @ Wikipedia
• URL @ Wikipedia