What is an IP Address?

What is an IP address?

An IP address identifies a network interface within an IP network and helps routers forward packets to their destination. A device can have several addresses, while several devices can share a public IPv4 address through NAT. An IP address therefore does not uniquely identify a person.

IPv4 and IPv6

IPv4 uses 32 bits and four decimal numbers from 0 to 255, such as 192.168.1.42. IPv6 uses 128 bits and hexadecimal groups, such as 2001:db8::42. That IPv6 example belongs to a documentation range. IPv6 provides more addresses but does not automatically encrypt traffic.

Public and local addresses

Private IPv4 ranges are 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. They are not routed on the public internet. IPv6 includes global, link-local and unique-local addresses. A globally addressed interface still needs appropriate firewall protection.

What does an IP address reveal?

Registration and GeoIP databases can suggest a network operator and region. Location estimates can be inaccurate or wrong, particularly for VPNs, mobile networks and anycast. An IP alone does not reliably reveal a home address. Dynamic addresses may change, but reconnecting does not guarantee a new address.