IP Address
About 5 min read
Last updated: 2026-03-20
What Is an IP Address
An IP address is a unique identification number assigned to every device connected to the internet. Just as a postal address is needed to deliver a letter, an IP address is used to route data to the correct destination on the internet.
When you browse a website, your device sends its IP address to the remote server, which then sends data back to that address. Without this mechanism, internet communication would not be possible.
Differences Between IPv4 and IPv6
There are two versions of IP addresses.
192.168.1.1. Still the dominant protocol on the internet, but address exhaustion has become a serious issue.2001:0db8::1. Adoption is growing, particularly through native IPv6 connections offered by major ISPs.IPv4 addresses were exhausted at the IANA (the central registry) level in 2011, and new allocations now assume a transition to IPv6. However, because NAT technology allows multiple devices to share a single public IPv4 address, a complete transition is still expected to take considerable time.
IPv4 Exhaustion and the Impact of CGNAT
IPv4 address exhaustion progressed in stages. IANA's central pool was depleted in 2011, and APNIC (the Asia-Pacific registry) ended normal allocations the same year. ARIN (North America) ran out in 2015, and RIPE NCC (Europe) in 2019.
To cope with this exhaustion, many ISPs have deployed CGNAT (Carrier-Grade NAT). Under CGNAT, hundreds to thousands of subscribers share a single public IPv4 address. While this makes it harder to identify an individual from a specific IP address, it also causes problems with IP-based access controls and rate limiting. A common example is being falsely banned from an online game server for "multiple connections from the same IP."
Public IP vs. Private IP
IP addresses fall into two categories based on their purpose.
- Public IP address: A globally unique address on the internet. Assigned by your ISP (Internet Service Provider), this is the address visible to external servers.
- Private IP address: An address used within a home or office network (e.g.,
192.168.x.x,10.x.x.x). Through the router's NAT function, multiple private IPs share a single public IP to access the internet.
When people say they want to "check my IP address," they usually mean their public IP address. The IP address displayed on our homepage is your public IP.
What Can Be Learned from an IP Address
When you visit a website, the following information can be inferred from your IP address.
- ISP (provider name): Which carrier's network you are using (e.g., Comcast, AT&T, Verizon)
- Approximate location: Location information ranging from state/province to city level. Accuracy depends on the ISP's infrastructure layout; it tends to be more precise in urban areas and less so in rural regions
- Connection type: Whether you are on a fixed-line connection (fiber), a mobile connection (4G/5G), or connecting through a VPN or data center
- AS number: A network identifier for the organization managing the IP address, used to determine whether access originates from a corporate network
Conversely, an IP address alone cannot reveal a person's name, home address, or phone number. Such information is held by the ISP and is not disclosed to third parties without a legal process.
How IP Geolocation Works and Its Accuracy
GeoIP (IP geolocation) is a technology that estimates geographic location from an IP address. Databases such as MaxMind's GeoLite2 and IP2Location are widely used.
Location estimation is based on databases that map which IP address blocks ISPs have assigned to which regions. For fixed-line connections, the ISP's regional facility location serves as the reference point, so discrepancies of several tens of kilometers from the actual location can occur. Accuracy drops further for mobile connections, where estimation is limited to the coverage area of a cell tower.
As a rough guide, accuracy at the country level exceeds 99%, but at the city level it drops to around 50-80%. When a VPN or proxy is used, the location of the exit server is displayed, producing results unrelated to the user's actual location.
IP Addresses and Privacy
While an approximate country- or region-level location can be estimated from an IP address, it cannot be used to identify a person's home address or name. In theory, an ISP could link an IP to subscriber information through a disclosure request, but this requires a court order.
If you want to enhance your privacy, you can hide your IP address using a VPN or Tor. However, even if you hide your IP address, tracking via browser fingerprinting and cookies requires separate countermeasures.
To learn more about this topic, see What Is an IP Address? How It Works and How to Check Yours.
Common Misconceptions
- Your home address can be identified from your IP address
- GeoIP only reveals information at the ISP facility level (roughly city-level). Identifying a personal address requires a legal disclosure request to the ISP, and an ordinary person cannot trace a home address from an IP address alone.
- Changing your IP address makes you completely anonymous online
- An IP address is just one of many tracking methods. You can also be tracked through cookies, browser fingerprinting, login credentials, and other identifiers, so changing your IP address alone does not make you anonymous.
- IPv6 is more secure than IPv4
- Encryption is handled by upper-layer protocols such as TLS, not by the IP version itself. IPv6 has no inherent security advantage, and in fact, IPv6-specific attack vectors (such as NDP spoofing) also exist.
Public IP vs. Private IP Comparison
Public IP
Globally unique on the internet. Assigned by the ISP. Directly accessible from outside. Limited in number (IPv4).
Private IP
Valid only within the local network. Assigned by the router. Not directly accessible from outside. Can be used freely.