IP Address
Internet Protocol Address
- In Turkish
- IP Adresi
In short
An IP address is a numeric label assigned to each device on a network so that data can be routed to it, much like a postal address for a house.
What is an IP address?
An IP address is a unique identifier given to every device that connects to a network using the Internet Protocol, such as a laptop, phone, server, or router. It tells other machines where to send data and where incoming data came from. Without IP addresses, computers on the internet would have no way to find each other.
Two versions are in use today. IPv4 addresses are 32-bit numbers written as four decimal parts, like 192.168.1.10, which allows about 4.3 billion addresses. IPv6 addresses are 128-bit numbers written in hexadecimal, like 2001:db8::1, and were introduced because the world was running out of IPv4 addresses. Routers read the destination IP address on each packet and forward it step by step toward its target.
Think of an IP address like a street address: the postal service does not care who lives in the house, only where to deliver the letter. Addresses can be public, meaning reachable from the internet, or private, such as 10.0.0.5 or 192.168.0.2, which work only inside a home or office network. A router using network address translation (NAT) lets many private devices share one public address.
IP addresses are often confused with domain names. A domain name like example.com is a human-friendly label, and DNS translates it into the IP address that computers actually use. An IP address is also different from a MAC address, which is a hardware identifier for a network card that is only used on the local network.
At a glance
Key takeaways
- An IP address identifies a device on a network so data can be routed to it.
- IPv4 uses 32-bit addresses like
192.168.1.10; IPv6 uses 128-bit addresses like2001:db8::1. - Private addresses work only inside a local network; public addresses are reachable from the internet.
- DNS translates human-friendly domain names into IP addresses.
- Many devices receive their IP address automatically, so it can change over time.
Example
# Show the IP addresses of this machine (Linux)
ip addr show
# Look up the IP address behind a domain name
dig +short example.com
# Check whether a device on the local network is reachable
ping -c 3 192.168.1.1Readers ask
What is the difference between IPv4 and IPv6?
IPv4 uses 32-bit addresses, which allows about 4.3 billion unique addresses, while IPv6 uses 128-bit addresses, which allows vastly more. IPv6 was created because IPv4 addresses ran out, and today most networks support both.
What is the difference between a public and a private IP address?
A public IP address is reachable from the internet and is unique worldwide. A private IP address, such as 192.168.1.20, is used only inside a local network, and the router translates it to a public address when traffic goes out.
Can two devices have the same IP address?
Not on the same network at the same time, because data would not know which device to reach. However, the same private address, such as 192.168.1.2, is reused in millions of separate home networks.
See also
- DNSDevOps & Cloud, p. 16DNS is the internet's naming system that translates human-readable domain names like example.com into the numeric IP addresses computers use to connect.
- TCPNetworking, p. 30TCP is a core internet protocol that delivers data between two programs reliably and in order, by opening a connection and resending anything that gets lost.
- PacketNetworking, p. 20A packet is a small, formatted unit of data sent across a network, made of a header with addressing information and a payload that carries the actual data.
- PortNetworking, p. 22A port is a number from 0 to 65535 that identifies a specific program or service on a device, so traffic reaching an IP address gets to the right application.
- VPNNetworking, p. 36A VPN is a technology that creates an encrypted tunnel between a device and another network, so traffic can travel privately across the public internet.
- FirewallNetworking, p. 8A firewall is a security system that checks network traffic and allows or blocks it based on rules, acting as a barrier between trusted and untrusted networks.
- IPv4Networking, p. 11IPv4 is the internet's original addressing system, using 32-bit addresses written as four numbers such as 192.168.1.10, allowing about 4.3 billion addresses.
- LocalhostNetworking, p. 15Localhost is the hostname for the computer you are using; it resolves to the loopback address 127.0.0.1 (::1 in IPv6), so its traffic stays on the machine.
Sources
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