An IP address is the number that identifies a device on a network so that data can be delivered to it. Every request your browser makes carries your address, so the web server knows where to send the reply. That is why every website you visit can see the address shown above.
Your home or office router usually has one public address on the Internet. The devices behind it are given private addresses from ranges reserved for local networks:
10.0.0.0 - 10.255.255.255 (10.0.0.0/8)
172.16.0.0 - 172.31.255.255 (172.16.0.0/12)
192.168.0.0 - 192.168.255.255 (192.168.0.0/16)
Private addresses are never routed across the Internet. Your router uses Network Address Translation (NAT) to share its public address between all of your devices, which is why this page shows the router's public address and not the address of your computer.
There are not enough IPv4 addresses for every customer to have one, so many mobile networks and some broadband providers share a single public address between many customers. Your router is given an address from the shared range 100.64.0.0/10, and the provider's equipment translates it to a public address that other customers also use.
Behind CGNAT you cannot forward ports to host a server or game from home, and a block placed on the shared address affects everyone using it. To check, compare the WAN or Internet address shown in your router with the address on this page. If the router shows an address from 100.64.0.0 to 100.127.255.255, you are behind CGNAT.
An IPv4 address is 32 bits, written as four numbers from 0 to 255 separated by dots.
That allows about 4.3 billion addresses, which have run out. An IPv6 address is 128 bits,
written as eight groups of four hexadecimal digits separated by colons. Leading zeros in
a group can be dropped, and one run of all-zero groups can be replaced with
::, so these are the same address:
2001:0db8:0000:0000:0000:0000:0000:0001
2001:db8::1
If your connection supports both, your browser will usually use IPv6, so this page may show either kind of address.
An IP address has two parts: the network it belongs to and the device within that
network. The split is given by the prefix length, written after a slash (CIDR notation).
In 192.168.1.0/24 the first 24 bits identify the network and the last 8 bits
the device, giving 256 addresses from 192.168.1.0 to 192.168.1.255. This is the same as
the subnet mask 255.255.255.0. A /16 covers 65,536 addresses.
The older classful scheme (Class A, B and C) fixed the split by the first number of the address. It was replaced by CIDR in 1993, so the position of a number in the address does not tell you whether it is part of the network or the device. In IPv6 each local network is normally a /64: the first 64 bits identify the network and the last 64 bits, the interface ID, identify the device.
Most home and mobile connections are given an address dynamically, and it can change when your router reconnects or restarts, or when the provider reassigns it. A fixed (static) address is usually available from your provider, often at extra cost. With IPv6, devices also use temporary privacy addresses that change regularly, so the interface ID can change even when the network prefix stays the same.
A VPN or proxy sends your traffic through its own server, so websites see that server's address instead of yours. Any location shown by a website that looks up your IP address will be the location of the VPN server.
The address on this page is your public address. To see the private address of the device you are using:
Windows : ipconfig (IPv4 Address under your active adapter)
macOS : ipconfig getifaddr en0
Linux : ip -4 addr
The server takes your address from the network connection itself, not from anything your browser sends. In code it is read like this:
PHP : $_SERVER['REMOTE_ADDR']
Delphi WebBroker : Request.RemoteAddr
Delphi Indy : ARequestInfo.RemoteIP (TIdHTTPServer.OnCommandGet)
When a site sits behind a proxy, load balancer or CDN, the connection comes from that
proxy, so the visitor's original address is passed on in the X-Forwarded-For
header. That header is ordinary text that any client can set, so only trust it when the
request came from a proxy you control, and use the address that your proxy added (the
last entry) rather than the first.
https://example.com:443/articles/page?name=value#section
• Scheme https : the protocol used to connect.
• Host example.com : the server, looked up through DNS to find its IP address.
• Port 443 : usually left out, because 443 is the default for https and 80 for http.
• Path /articles/page : the page or file on that server.
• Query name=value : extra values for the page, after the ?.
• Fragment section : a position within the page, after the #.
It is used only by the browser and never sent to the server, which is why it cannot be
shown in The Address You Requested above.