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IP address

An IP address is a number used to identify a network destination so that internet data can be sent to it across networks. People usually type a domain name, but computers use IP addresses as part of moving data between networks.

What does an IP address look like?

Two versions are in common use. An IPv4 address has four numbers separated by dots, such as 192.0.2.53. An IPv6 address uses groups of hexadecimal characters (digits and the letters a to f) separated by colons, such as 2001:db8::53. These two example addresses are reserved for documentation; they illustrate the formats and are not the live addresses of a website.

IPv6 provides many more possible addresses than IPv4. Networks can use either version or both. A person does not need to memorize the address to visit a site: a domain is easier to read, and DNS can return the IP address or addresses currently associated with a name.

How does an IP address help data reach a service?

Suppose Alex enters https://example.com in a browser. The browser asks DNS for address information for example.com. DNS may return an IPv4 address, an IPv6 address, or both. The browser can then send network traffic toward an address that can handle the request. The IP address helps routers move that traffic across networks; the domain name and web service help determine which site or resource the browser is asking for.

The relationship is not always one name to one permanent address. A service can use several IP addresses, and an address can change when the service or network is reconfigured. Large sites may return different addresses in different places or at different times. The address is part of how traffic is routed, not a permanent label for a particular page.

Are all IP addresses public?

No. A public IP address can be routed across the public internet. A private IP address is used within a local network, such as a home or office, and is not routed directly across the public internet. For example, a home router can give a laptop a private address and use a public address for the home’s internet connection. The router then translates traffic between the local network and the internet. As a result, several devices in a home or organization can appear to outside services to share a public IP address.

An IP address does not necessarily identify one person or a precise physical location. A public address may be registered to an internet provider or organization, and it may be shared by many users. Address registration data can help identify the network or provider responsible for an address range, but it does not by itself prove which person used a connection at a particular time.

How is an IP address different from a domain name?

A domain is a human-readable name. An IP address is a numeric network address used to route traffic. DNS connects these roles by providing address information for names. If Alex changes the IP address used by her hosting service, she can keep example.com and update its DNS information. Visitors can continue using the same name after the updated information is available to the DNS services that look up answers for them.

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