Next are third-level domains, which are written immediately to the left of a second-level domain. There can be fourth- and fifth-level domains, and so on, with virtually no limitation. An example of an operational domain name with four levels of domain labels is sos.state.oh.us. Each label is separated by a full stop (dot). 'sos' is said to be a sub-domain of 'state.oh.us', and 'state' a sub-domain of 'oh.us', etc. In general, subdomains are domains subordinate to their parent domain. An example of very deep levels of subdomain ordering are the IPv6 reverse resolution DNS zones, e.g., 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa, which is the reverse DNS resolution domain name for the IP address of a loopback interface, or the localhost name.
Yes. We recommend buying not only your domain name with your favorite extension (eg. .com), but also additional, alternative domain extensions (eg. .net, .info, etc). The reason is simple. Having more than one domain extension strengthens your online identity, secures your brand name and improves your online presence. Buying more than one domain extension also protects you from your competitors registering your additional extensions and enticing away your customers.
Once you've wisely determined that building a website is an essential part of your business, you need to make another important decision, even before you consult our roundup of the best web hosting services: What's your domain name going to be? You know, it's the [yoursitename].com web address by which all your (hopefully) many customers will find you. Furthermore, how do you go about staking your claim for it? Purchasing a name is a relatively simple process (although finding one that isn't already taken can be a challenge), but there are many factors that you should consider. Since your domain name is, in effect, the name of your website, you want to make sure you get a good one. But what makes a good one? And since it's also the address of your website, you want to make sure you understand the contract between you and the domain name registrar. Is it starting to sound a little more complicated? Don't worry: This primer can help you get started.

A domain name consists of one or more labels, each of which is formed from the set of ASCII letters, digits, and hyphens (a-z, A-Z, 0-9, -), but not starting or ending with a hyphen. The labels are case-insensitive; for example, 'label' is equivalent to 'Label' or 'LABEL'. In the textual representation of a domain name, the labels are separated by a full stop (period).


Domain names are organized in subordinate levels (subdomains) of the DNS root domain, which is nameless. The first-level set of domain names are the top-level domains (TLDs), including the generic top-level domains (gTLDs), such as the prominent domains com, info, net, edu, and org, and the country code top-level domains (ccTLDs). Below these top-level domains in the DNS hierarchy are the second-level and third-level domain names that are typically open for reservation by end-users who wish to connect local area networks to the Internet, create other publicly accessible Internet resources or run web sites.
The suffix identifies the name as belonging to a specific top-level domain (TLD). As of late 2016, when this article was written, there are numerous TLDs available for general purchase, including .com, .edu, .game, .green, .hiphop, .net, and .org. The most popular of these by far is .com, which is supposed to indicate commercial sites, but in reality has come to include almost everything.
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 purchase or transfer a domain to Google Domains, you can immediately start creating your website with one of our website building providers. Plans vary in cost, and options include secure and reliable hosting, customizable templates, and powerful features like drag & drop creation and mobile site-management. To learn more, visit the Help Center.
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