What is IP?
Author: Domeny.ForSale editorial team Published
In brief: IP stands for Internet Protocol, a set of rules for transmitting data between networks. In everyday usage, “IP” means an IP address — a number assigned to a device’s network connection that helps direct data to the right destination. This address is not a permanent identifier of a person: it can change, and many devices often share a single public address.
What is an IP address used for?
When you open a website, your computer sends a request to a server, and the server sends a response back. IP addresses identify the source and destination of packets being transmitted — small portions of data. Routers — devices that connect networks — use the destination address to forward packets.
You can compare this to addressing parcels, although an IP address does not directly identify a home or a person. It relates to a network connection, so a laptop may have one IP address on your home Wi-Fi, another at the office, and yet another when connected through your phone. A single device can also have several addresses at once.
A domain name, such as example.com, is not an IP address. DNS, the Domain Name System, lets you find the addresses needed to connect to a service operating under a particular name. This means you can enter a readable name instead of remembering a string of digits. One domain can point to many IP addresses, and one address can serve many websites.
IPv4 and IPv6: two address formats
You will encounter two versions of the IP protocol on networks: IPv4 and IPv6. Both are used for addressing and transmitting data, but they use different formats and have different numbers of available addresses.
| Version | Example address | Key characteristic |
|---|---|---|
| IPv4 | 192.168.1.20 | Four numbers from 0 to 255 separated by dots; a limited pool of addresses |
| IPv6 | 2001:db8::20 | Hexadecimal notation separated by colons; a much larger pool of addresses |
The IPv4 example in the table is a private address, while the IPv6 example comes from a range reserved for documentation. A double colon in IPv6 shortens a sequence of groups of zeros. You do not need to choose the protocol version yourself when browsing websites normally — your device and network usually determine how to connect automatically.
Public, private, static and dynamic IP addresses
A public IP address is used for communication over the public internet. However, this does not mean that every device with such an address accepts connections from outside: a firewall or service settings may block access.
A private IPv4 address works within a local network, such as your home network. Typical ranges are 10.x.x.x, from 172.16.x.x to 172.31.x.x, and 192.168.x.x. The same addresses can appear in many separate home networks because they are not routed directly over the public internet.
For example: a laptop has the address 192.168.1.20, and a phone has 192.168.1.21. The home router may use NAT, or network address translation, which allows both devices to connect to the internet through a single public IPv4 address. The provider may also use CGNAT — sharing a public address among many customers. This often makes it difficult to make a home server accessible from outside.
The distinction between static and dynamic IP addresses concerns something different. A static address remains assigned according to the configuration or terms of the service; a dynamic address may change, though not necessarily every time the router restarts. A public address can be dynamic, while a private one can be set to remain static.
You usually do not need a static IP address to browse websites. When planning remote access to your own server, ask your provider about a public address, CGNAT, IPv6 support and restrictions on incoming connections. Check the provider’s current offering for availability and any fees.
How can you check your IP address?
First, establish which address you are looking for. To configure a printer, you usually need a local address; to diagnose a connection to an internet service, a public address is more often useful.
- Windows: open Command Prompt, enter
ipconfigand find the IPv4 or IPv6 address listed for the active connection. - macOS: open the network settings and the details of the active Wi-Fi or Ethernet connection.
- Phone: check the details of the connected Wi-Fi network; option names depend on the operating system and manufacturer.
- Public IP: check your router’s control panel and a service that displays the address from which your connection arrives. With CGNAT, the address shown in the router’s control panel may differ from the one visible on the internet.
If you use a VPN, a tunnel that routes traffic through another server, an IP-checking website will usually show the VPN’s exit address. The result may also depend on whether the connection uses IPv4 or IPv6.
What does an IP address reveal about a user?
A public IP address can often be used to identify the provider or organisation managing that address range, as well as an approximate location. The city shown may be incorrect, especially with mobile networks, VPNs and corporate connections. The address alone does not reliably reveal a person’s name or exact home address.
A server you connect to without an intermediary sees the connection’s public source address. This does not automatically mean it has access to your files. The risk depends primarily on the services accessible from the internet, their security measures and updates. Changing your IP address, in turn, does not ensure anonymity, because websites can also recognise users through their logged-in accounts or cookies.
If you are checking your IP because of a network problem, note down the local address, public address and whether a VPN is active. Together, these details will make it easier to distinguish a home network configuration error from restrictions imposed by the provider.
See also: What is CERT Polska?
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