An IP address (Internet Protocol address) is a number that identifies a device on a network and tells other devices where to send data. IPv4 addresses look like 192.168.1.42 and IPv6 addresses look like 2001:db8::1. Your home has one public address and each device has a private one.
01 Check Your Own IP Address Right Now
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Network Identity panel
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The full panel adds ASN, routing type, proxy and hosting flags and a map. See also the Network Route panel for who owns your network.
An IP address (Internet Protocol address) is a number assigned to a device on a network so that data can be sent to it and answered. It does two jobs at once: it identifies the device and it says where in the network the device sits. The format is defined in RFC 791.
An IPv4 address is four 8-bit numbers. Part of it names the network and the rest names the device.
The split between network and host is set by a subnet mask. That is why two devices on the same home network share their first numbers and differ only at the end.
03 Public vs Private IP Addresses
Your home has one public address from your ISP, but every phone, laptop and printer inside has a private one. A router running NAT (network address translation) rewrites private addresses to the public one on the way out. If you want to find a device inside your network, start with the guide to finding the IP address of any device.
Three devices with private addresses reach the internet through one public address on the router.
Rule of thumb: an address starting 192.168, 10 or 172.16 to 172.31 is private. If a website shows you a different address, that one is your public IP.
The reserved ranges you will meet most often. Anything outside them is public.
Public and private addresses compared
Feature
Public IP
Private IP
Reachable from the internet
Yes
No, only on the local network
Assigned by
Your ISP
Your router (DHCP)
Unique worldwide
Yes, at a given moment
No, reused in every home
Example
203.0.113.7
192.168.1.42
Shows your approximate location
Yes (an estimate)
No
04 How Data Finds You
When you open a website, your device sends a packet addressed to the site's IP address. Each router on the way reads only the destination, picks the next hop and forwards it. The reply comes back to the source address, which is how the web works without any central map. The names you type are turned into these addresses by DNS.
A request travels hop by hop. Each router only needs to know the next step toward the destination.
05 IPv4 vs IPv6
IPv4 has 232 addresses, about 4.3 billion. IANA handed its last free IPv4 blocks to the regional registries in 2011, which is why NAT is so common. IPv6, specified in RFC 8200, uses 128 bits, enough that NAT is not needed for scarcity.
IPv4 compared with IPv6
Feature
IPv4
IPv6
Length
32 bits
128 bits
Written as
Four decimal numbers: 192.0.2.1
Eight hex groups: 2001:db8::1
Address count
About 4.3 billion
About 3.4 x 1038
Needs NAT
Usually
No
Private equivalent
10/8, 172.16/12, 192.168/16
fc00::/7 (unique local)
06 Static vs Dynamic Addresses
Most addresses are dynamic: a DHCP server lends one to your device for a limited time, defined in RFC 2131. A static address is set by hand or reserved on the router and does not change, which suits printers and servers.
DHCP gives a device an address in four steps and the device renews it before the lease ends.
07 What Your IP Address Reveals
An IP address reveals your ISP, your network type and an approximate region. It does not reveal your name, street address or the contents of what you do. Location comes from databases that estimate it, so it can point to the wrong city, especially on mobile networks and VPNs. To see how your connection is classified, use the VPN and Proxy panel, and for a deeper look at lookups from the other side read what a reverse IP lookup is.
08 Reading an Address: Subnet Masks and CIDR
An address always comes with a subnet mask, which says how much of it names the network and how much names the device. The short form, CIDR, writes the number of network bits after a slash. 192.168.1.42/24 means the first 24 bits are the network.
Worked example. For 192.168.1.42 with mask 255.255.255.0 (/24), the network is 192.168.1.0, usable device addresses run from .1 to .254, and .255 is the broadcast address. Two devices talk directly only if they share the same network part.
Common masks
CIDR
Subnet mask
Usable devices
/8
255.0.0.0
16,777,214
/16
255.255.0.0
65,534
/24
255.255.255.0
254
/30
255.255.255.252
2
Most home networks use /24, which is why router and device addresses usually differ only in the last number.
09 Addresses That Signal a Problem
Some addresses tell you what is wrong before you look anywhere else.
Problem addresses
Address
What it means
What to do
169.254.x.x
No address was assigned, so the device made one up (link-local)
Check the cable or Wi-Fi and restart the router
0.0.0.0
No address configured yet
Reconnect to the network
127.0.0.1
Loopback: the device talking to itself
Normal, but not a network address
Same address on two devices
Address conflict
Give one device a reservation or a new address
Seeing 169.254 is the most common of these, and it almost always points to the router or the connection, not the device.
Frequently Asked Questions
12 questions on this topic.
It gives a device a numeric address so data can be sent to it and so replies can come back. Every packet carries a source and a destination IP address, and routers use the destination to forward it.
No. A MAC address identifies a network adapter on the local link and normally stays with the hardware. An IP address identifies a device on a network and can change as you move between networks. See whether a VPN changes your MAC address.
A public IP address is reachable on the internet and is assigned by your ISP. A private address, such as 192.168.1.42, works only inside your local network and is reused by millions of homes. Your router translates between them with NAT.
Not directly. An IP address maps to an ISP and an approximate area, not to a street address. Only your ISP can link the address to your account, and it normally discloses that only through legal process. IP location is an estimate and can be wrong by a wide margin.
Some ISPs place many customers behind one shared address using carrier-grade NAT (the 100.64.0.0/10 range). In that case the router's WAN address is not the one websites see. The Network Route panel shows the address and network the internet sees.
IPv6 is the newer 128-bit addressing system designed to replace IPv4, which has only about 4.3 billion addresses. You do not have to configure anything: most devices run both versions, and your ISP decides whether you get IPv6.
It is a private address that many routers use as their default gateway, so you type it into a browser to open router settings. It is a convention, not a rule: your router may use 192.168.0.1, 10.0.0.1 or another address.
Yes. While connected, websites see the VPN server's IP address instead of yours. Leaks such as WebRTC can still expose your real address, which the WebRTC leak test checks, and the VPN and Proxy panel shows how your connection is classified.
Usually yes, since every site you visit already receives it. It reveals your ISP and an approximate location, and a public IP can be targeted for denial-of-service attacks, which mostly concerns gamers and streamers. Avoid posting it publicly and use a VPN if that is a concern.
Often yes. Most home connections get a dynamic address from the ISP, and your device gets a private address from the router by DHCP. Either can change when a lease expires or equipment restarts, while a static address is configured to stay the same.
It means the first 24 bits are the network part, which equals the mask 255.255.255.0 and allows 254 usable devices.
It is the loopback address, which a device uses to talk to itself. It never leaves the device.
Logic
Explain the address first as a label (what), then as a route (how), then as a privacy signal (what it reveals), because each step depends on the previous one.
Methodology
Definitions and ranges follow the RFCs listed below. The live check reads your connection's public IP through the IntelReap backend; location fields are estimates. Example addresses come from reserved documentation ranges.