Second-level (or lower-level, depending on the established parent hierarchy) domain names are often created based on the name of a company (e.g., bbc.co.uk), product or service (e.g. hotmail.com). Below these levels, the next domain name component has been used to designate a particular host server. Therefore, ftp.example.com might be an FTP server, www.example.com would be a World Wide Web server, and mail.example.com could be an email server, each intended to perform only the implied function. Modern technology allows multiple physical servers with either different (cf. load balancing) or even identical addresses (cf. anycast) to serve a single hostname or domain name, or multiple domain names to be served by a single computer. The latter is very popular in Web hosting service centers, where service providers host the websites of many organizations on just a few servers.
When you type google.com into your browser, the domain is split into parts by the “dot”, from right to left. The first part is “com”, so your computer checks the root zone file to see which registry manages the .com TLD. It then checks with this registry to see where the next part, “google”, points to. The registry returns the IP address 126.96.36.199, and your computer can then ask Google to send their homepage over.
DNS is essentially a database of IP addresses. Each IP address is a series of numbers that allow computers to communicate with each other. A website is identified on a server by its IP address. Instead of your visitors having to remember an IP address to type into their browser to access your site, they instead use your domain name. When your domain is entered into their browser, DNS translates it into an IP address because that is what computers understand.Your computer is able to connect to your web hosting and show your website on the browser once the IP address is found.
Sedo is where I bought my domain - over Escrow - and is a global marketplace to buy, sell, and park domain names. They've over 18 million domain names for sale, but the big part is that they're a huge, well-respected company. This may not be important if you're spending $150 on a domain, but in a $15,000+ purchase - which happens in many cases - you will be potentially buying from a foreign entity, that you don't know, and many of them will suggest an escrow payment. This means you put the money in an account owned by a third party that will hold it and only pass it on once the domain has been transferred over into their name (which in this case is what Sedo does). This can be quite disconcerting - but Sedo is well-known and has done many, many deals - and the process is about as full of hand-holding as handing tens or hundreds of thousands of dollars for a domain name can be.
The hierarchy of domains descends from the right to the left label in the name; each label to the left specifies a subdivision, or subdomain of the domain to the right. For example: the label example specifies a node example.com as a subdomain of the com domain, and www is a label to create www.example.com, a subdomain of example.com. Each label may contain from 1 to 63 octets. The empty label is reserved for the root node and when fully qualified is expressed as the empty label terminated by a dot. The full domain name may not exceed a total length of 253 ASCII characters in its textual representation. Thus, when using a single character per label, the limit is 127 levels: 127 characters plus 126 dots have a total length of 253. In practice, some domain registries may have shorter limits.
Administrative contact. A registrant usually designates an administrative contact to manage the domain name. The administrative contact usually has the highest level of control over a domain. Management functions delegated to the administrative contacts may include management of all business information, such as name of record, postal address, and contact information of the official registrant of the domain and the obligation to conform to the requirements of the domain registry in order to retain the right to use a domain name. Furthermore, the administrative contact installs additional contact information for technical and billing functions.
HostGator is a company I used for many years with an old firm, and I've found them to be fairly reliable as a rock-solid grounding for a bandwidth-heavy site. Their control panel is also fairly powerful, allowing you to automatically control your fleet of names, as well as locking them down so that nobody can snipe them if you accidentally let a renewal lapse. Their prices are competitive but not the best, but I've found them to be immensely reliable in the past. Read our HostGator Review.