POP's Domain and DNS Glossary

Getting online can be a complex process. People throw around a lot of terms and acronyms that can be hard to sort through. Our goal is to make that easier for you. Starting with this glossary of terms related to domain names, DNS management, and other factors of getting an idea online.

If there is a term you are looking for, and you don't find it here, just tweet or email us, and we are happy to add it!


301 redirect

A 301 redirect refers to a permanent move from one URL to another URL-- like if you rename your site from reallygreatsite.com to the shorter-and-sweeter greatsite.co. Search engines recommend that webmasters use 301 redirects when moving a webpage to make sure that both search engines and users are routed to the proper destination page.

302 Redirect

A 302 redirect also indicates a move to another webpage; however, unlike a 301 redirect, which is permanent, a 302 redirect is temporary. So, when webmasters are moving a webpage permanently, a 301 redirect is usually used instead of a 302.

404 Error

A 404 error is an error message that indicates a webpage was not found by a server. It is a HTTP standard response code that is sent to a browser when the user has typed an incorrect URL, attempted to access a Web page that’s no longer available, or clicked on a broken link on another webpage. Lots of companies create interesting 404 pages to delight their users, like the ones seen here.


A record

An A Record is short for an Address record. In simple terms, A Records—also called host records—assign an IP address to a domain name. Multiple A Records can be configured for one domain name, and different subdomains of a website may be resolved to different IP addresses, which is really useful if they are hosted on different servers.




A CNAME Record, also sometimes written as C NAME, allows the webmaster to point a hostname to another domain name or subdomain. The CNAME record indicates the canonical host name of a computer that has different aliases. When a name server looks up a name and finds a CNAME record, it replaces the name with the canonical name and looks up the new name. This allows webmasters to point multiple systems to one IP without specifying an A record for each host name.

Canonical Name Record

Just a fancy term for a "CNAME" -- see above



DNS is an acronym for Domain Name System. DNS is a naming system (hierarchical in nature) which names computers, services, servers or any other resource connected to the Internet or a private network. Primarily, it maps domain names to corresponding IP addresses.

Domain Forwarding

Domain name forwarding is the process of directing a website’s visitors to a different, existing website. There are many ways to go about doing this--301 and 302 redirects are two of the most common methods.

Domain Name

A domain name is a name that identifies an internet resource, such as a website. It is the portion of a network address that identifies it as belonging to a particular domain. Domain names are unique, case insensitive, and comprised of alphanumeric characters and hyphens.





Host Record

In simple terms, Host Records—also called A Records—assign an IP address to a domain name. Multiple Host Records can be configured for one domain name, and different subdomains of a website may be resolved to different IP addresses, which is really useful if they are hosted on different servers.



ICANN is short for Internet Corporation for Assigned Names and Numbers. ICANN is a nonprofit organization that holds the responsibility for IP address space allocation, generic (gTLD) and country code (ccTLD) Top-Level Domain name system management, protocol parameter assignment, and root server system management. These functions were all previously performed under U.S. Government contract.

IP Address

An IP address (Internet Protocol) is a numerical label assigned to each machine on a particular network. Each device on a network—computer, smartphone, printer, etc.-has an IP address assigned to it, which allows the devices to “communicate” with each other. There are two standards for IP addresses: IP Version 4 (IPv4) and IP Version 6 (IPv6). All computers with IP addresses have an IPv4 address, and many computers are also beginning to adopt the new IPv6 address system.


IPv4 is short for Internet Protocol Version 4, and is the fourth revision of the Internet Protocol. In basic terms, it is the technology that allows us to connect our devices to the internet. Through this technology, IP addresses are used to identify devices on a network through an addressing system. IPv4 supports 32-bit addresses, which translates into ^32 IP addresses in total — approximately 4.29 billion. Although this is a huge number, the internet is actually running out of IP addresses—that's where IPv6 comes in.


IPv6 is the newest revision of the Internet Protocol. IPv6 supports 128-bit versus 32-bit addresses. 128-bit addresses translates into 2^128 Internet addresses - 340,282,366,920,938,000,000,000,000,000,000,000,000. The transition from IPv4 to IPv6 has been very slow, and IPv4 is currently still accounting for 96% of internet traffic.





MX Record

A DNS MX record refers to a Mail Exchange record, and represents a significant part of an email delivery system. The MX records "tell" other computers what server to send email to. One domain can have multiple mail routes, which are each assigned a priority number; the lowest number identifies the server responsible for the domain.



A name server is a web server that responds to requests from components such as a web browser. The name server maps an identifier such as a website’s domain to a numerical label, like an IP address. This makes it possible for a user to access a website by typing in the actual domain name instead of the website's IP address. People write it as both "Nameserver" (one word) and "Name Server" (two words), both are correct, people are just funny that way.



Private Registration

Private registration is a service offered by several domain name registrars. By default when a domain is purchased, the buyer’s contact information is listed within the WHOIS directory. But, with private registration, buyers purchase privacy from the company, who in turn replaces their contact info in the WHOIS directory with the info of a forwarding service—also called proxy services.

Proxy Service

Proxy services allow a domain name to keep certain identity and contact details from appearing in the public WHOIS directory—this is called private registration. The proxy service becomes the registered name holder of record, and its identity and contact information is displayed in WHOIS, instead of the contact info of the purchaser.




A redirect is a web server function that sends a user from one URL to another. There are several different types of redirect HTTP response codes, each serving a different function. These include a 301 redirect (permanent), a 302 redirect, (temporary), 303 redirect (returns a “see other” status”, and a 410 redirect (indicating the resource has been replaced). Redirects are used for many different reasons—one of the most common reasons is to direct content from one domain name to a new one.


A registrant is the individual or organization registering a domain name. When you submit your application for your desired domain name, you automatically become the domain name registrant.


A registrar refers to an organization that manages the reservation and registration of Internet domain names. Legitimate registrars are accredited by ICANN. Registrars enable you to find, reserve and register your desired domain name—granted that it is available—and make it so that nobody else can secure it.


A domain name registry is a database of all domain names and the linked registrant information in the top level domains of the Domain Name System (DNS). Domain name registries contract with registrars in order to allow the public to register domain names.


A reseller applies to an individual or organization that resells domain names through a registrar reseller program. During this process, domains are still registered through the registrar, but resellers are able to offer the domain registration services at their own websites and earn a profit from every domain that is registered.







WHOIS is the query and response protocol which finds information about a particular domain name or IP address. This information usually includes the name, address, and phone number of the administrative, billing, and technical contacts of the domain name. You can also use WHOIS to check if a domain name is available or if it has already been registered.