An Internet Protocol address (IP address) is a numerical label such as 192.0.2.1 that is assigned to a device connected to a computer network that uses the Internet Protocol for communication. IP addresses serve two main functions: network interface identification, and location addressing.
Picture a large office building with a single street address. Mail arrives at that address all day long, but it needs to reach different companies on different floors. The suite number on each envelope tells the mailroom exactly where to route each delivery. Network ports work the same way. Your computer's IP address is like the building's street address. It gets traffic to the right machine. The port number is like the suite number. It gets traffic to the right application running on that machine. Technically, a port is a 16-bit number, which means it can range from 0 to 65,535. When you visit a website, your browser connects to port 443 on the web server. When you send an email, your mail client connects to port 587 or 465. Each application listens on its assigned port, ready to handle incoming data. The combination of an IP address and port number is called a socket. You might see this written as 192.168.1.100:443, where the number after the colon is the port. This notation uniquely identifies a specific service on a specific machine, allowing billions of simultaneous connections across the internet without any confusion about where data should go.
IPv4 - Internet Protocol version 4 (IPv4), is the original addressing system of the Internet, introduced in 1983. It uses a 32-bit address scheme, which theoretically allows for over 4 billion unique addresses (2^32). IPv4 addresses are typically displayed in decimal format, divided into four octets separated by dots. For example, 192.168.1.1 is a common IPv4 address you might find in a home network.
IPv6 - Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated problem of IPv4 address exhaustion, and was intended to replace IPv4. In December 1998, IPv6 became a Draft Standard for the IETF, which subsequently ratified it as an Internet Standard on 14 July 2017.
About protocols for IP addresses...
Because of how IPv6 addresses are written, compression is used so they can be written faster, clearer, and more comfortably:
Uncompressed IPv6 address: 2001:0db8:0047:0000:0000:0000:587b:0001
Compressed IPv6 address: 2001:db8:47::587b:1
:: can be used to replace consecutive blocks of zeros, but it can only be used once in an address and specific rules apply.
Not all IP addresses are meant for public use. For example:
The ranges 10.0.0.0 to 10.255.255.255, then 172.16.0.0 to 172.31.255.255, and 192.168.0.0 to 192.168.255.255 are intended for use within private networks, similarly the range fe80:: to fe80:ffff:ffff:ffff:ffff:ffff:ffff:ffff in IPv6.
About reserved IP address ranges...
A dynamic IP address is a temporary address for devices connected to a network that continually changes over time, while a static IP address is simply an address that doesn't change. Once your device is assigned a static IP address, that number typically stays the same until the device is decommissioned or your network architecture changes. Most internet users use a dynamic IP address.
About dynamic and static IP addresses...
1. "An IP address uniquely identifies a person." - In reality, IP addresses change frequently and can be shared by multiple people or devices.
2. "An IP address always shows exactly where you live." - Many IP addresses only reveal an approximate location and not an exact address.
3. "Private IP addresses are available on the Internet." - Private IP addresses (e.g. 192.168.1.1) are only used within private networks.
4. "A VPN makes you completely anonymous." - A VPN only changes your public IP address, and websites can still use other tracking methods.
5. "Knowing someone's IP address means you can hack them." - An IP address alone does not reveal vulnerabilities unless it is associated with security flaws.
About common misconceptions about IP addresses...
You can use websites such as IPinfo to find out the approximate location of an IP address.