What Is an IP Address?
How an IP Address Identifies a Device
What is an IP address? An IP address (Internet Protocol address) is a numerical label assigned to a device or network interface so that other devices can send it data. It works like a postal address for packets of information, telling the network where each piece of traffic should be delivered.
Every computer, phone, router and server that communicates over the internet has at least one IP address. Each packet of data carries a source and a destination address in its header. Routers read the destination and forward the packet toward the network that owns that address, step by step, until it arrives.
How Domain Names Connect to IP Addresses
People prefer names such as example.com to strings of digits, so the Domain Name System translates a name into the IP address a browser needs. When you type a domain, your device asks a DNS resolver which address belongs to that name. The browser then connects to the address it receives. The name itself is not used for routing; the address is what the network follows.
This is why a website can move to a new server without changing its name. Only the DNS record changes, pointing the name to the new address, and the site remains reachable at the same domain. The lookup itself is covered in how DNS works.
Where IP Addresses Come From
IP addresses are handed out in blocks. Regional internet registries allocate large ranges to internet providers and hosting companies, who then assign single addresses to their customers and servers. A hosting company, for example, owns a block and places a server on one of its addresses. Blocks are written in shorthand such as /24, which is explained in the article on subnets.
Some addresses stay assigned for long periods, while others change when a connection is renewed. The difference between the two is covered in the comparison of IPv4 and IPv6, which describes the two address formats in use today.
Frequently asked questions
Can two devices have the same IP address?
On the same network, no. Each device needs a unique address so that traffic reaches the right machine. Across different networks, the same private address can be reused, because each network has its own space and translates traffic at its edge. Public addresses, however, must be unique across the whole internet.
Is an IP address the same as a domain name?
No. A domain name is a readable label, such as example.com, and an IP address is the numeric location that the name points to. One domain can point to several addresses, and one address can host many domains. The Domain Name System maps names to addresses so that people never have to memorize the numbers.