DNS Terminology

Dynamic IP

A dynamic IP address changes each time you connect to your Internet Service Provider (ISP). This allows ISPs to keep a pool of addresses available to subscribers. If you disconnect from the ISP, your address is returned to the pool, becoming available to the next computer that connects.


DNS stands for Domain Name Service. DNS servers translate names, such as “yourname.com” into the numeric IP address that the Internet uses to send and receive information. Most ISPs and companies run their own DNS servers, and there are thousands of them on the Internet.

Domain Name

A domain name is a name given to an organization of computers on the Internet. For example, “google.com” and “yahoo.com” are domain names.

Dynamic DNS

A process of performing an RFC 2136 “DNS Update” to add, modify or delete DNS resource records on the fly without reloading the entire DNS zone master file.


Is a protocol that is very commonly used in computer networks.

Fully Qualified Domain Name (FQDN)

A Fully Qualified Domain Name is the combination of a hostname and a domain name, with the hostname being to the left of the domain name. For example: “www.google.com” and “www.yahoo.com” are fully qualified domain names.

File Transfer Protocol (FTP):

An Internet protocol designed for the purpose of a client downloading files from an FTP server. No-IP.com does not provide FTP space but our users are encouraged to run their own FTP server.


A Host or Hostname is a textual name given to a computer. A computer can have more than one name. Common hostnames are “www”, “mail” and “ftp”, but you can name a host just about anything.

Hyper Text Transfer Protocol (HTTP)

HTTP is the standard protocol used by web servers to transmit data back and forth to your browser.

Internet Protocol Address (IP)

The Internet Protocol (IP) address is assigned to your computer, providing a numeric address necessary for connecting to the Internet or another IP-based network.


The Internet is a large collection of computers that are inter-connected and using the TCP/IP protocol to communicate.

Internet Service Provider (ISP)

A company that provides individuals and other companies access to the Internet and other related services such as website building and email services.

Post Office Protocol (POP3)

Is an Internet standard protocol that is used to allow users to download their email to their computer from the mail server.

Port 25

This is the standard port that mail servers listen on. Many ISP’s block inbound and outbound port 25 to stop spammers from abusing their networks. This makes running a mail server on one of these ISP’s networks nearly impposible. See Mail Reflector and Alternate-Port SMTP for No-IP based solutions to get around this problem.

Port 80

This is the standard port that web(http) servers run on. Many ISP’s have blocked port 80 to stop viruses such as Nimda from slowing down their networks and infecting their customers computers. Use No-IP’s port redirect or web redirect host type to get around this issue.

Root Nameserver (Root Server)

A root nameserver is a DNS server that answers requests for the root namespace domain and redirects requests for a particular top-level domain to that TLD’s nameservers.


A Registrar is the company or organization that you purchased or registered your domain name through.

Static IP

A static IP address is fixed, much like a telephone number. If your ISP gives you a static address, you will always use the same address. Servers usually have static addresses, so they can always be found at the same location.

Simple Mail Transport Protocol (SMTP)

This is an Internet standard protocol that is used to send outgoing email over the internet to an email (SMTP) server.


Spam is unsolicited bulk or junk email.

Top Level Domain

The highest level in the Domain Name System hierarchy. The portion of the domain name that comes after the dot “.” (.com, .net, .org, .uk).

Terms of Service (TOS)

No-IP’s terms of service agreement can be viewed here.

Universal Resource Locator (URL)

A URL is a way to specify the location of something found on the Internet. A URL typically points to a website and appears as a link on web pages.

Web Redirect

Also known as HTTP Redirect or URL Redirect. Replace a long url with an easy to remember shorter one using a web redirect. http://www.somefreeisp.com/community/pages/members/some_page.html becomes http://mypage.no-ip.com/