When you use the Web or send an e-mail message, you use a domain name to do it. For example, the URL “http://www.megrisoft.com” contains the domain name megrisoft.com. So does the e-mail address “firstname.lastname@example.org.”
Human-readable names like “megrihost.com” are easy for people to remember, but they don’t do machines any good. All of the machines use names called IP addresses to refer to one another. For example, the machine that humans refer to as “www.megrisoft.com” has the IP address 220.127.116.11.
Domain name servers translate domain names to IP addresses.
The DNS system is a database, and no other database on the planet gets this many requests. No other database on the planet has millions of people changing it every day, either. That is what makes the DNS system so unique!
To keep all of the machines on the Internet straight, each machine is assigned a unique address called an IP address. IP stands for Internet protocol, and these addresses are 32-bit numbers normally expressed as four “octets” in a “dotted decimal number.” A typical IP address looks like this:
Every machine on the Internet has its own IP address. A server has a static IP address that does not change very often. A home machine that is dialing up through a modem often has an IP address that is assigned by the ISP when you dial in. That IP address is unique for your session and may be different the next time you dial in. In this way, an ISP only needs one IP address for each modem it supports, rather than for every customer.