Public vs Private IP Addresses Explained
In computer networking, IP addresses are split into two primary domains: Public and Private. This separation was introduced to save IPv4 addresses from rapid depletion and to protect local networks from direct external access.
What is a Public IP Address?
A public IP address is assigned to your network router by your Internet Service Provider (ISP). It is globally unique across the entire internet. When you visit a website, your router uses this public IP address to request the data. Every device on your local network shares this single public IP when communicating with the outside world.
What is a Private IP Address?
A private IP address is assigned locally to devices (like your phone, laptop, or smart TV) inside your home network by your router. These addresses are not routeable on the public internet. This means multiple homes can use the exact same private IP address ranges simultaneously without conflicts. If you need to view your local or external address, check our guide on how to find your IP address.
Private IP Address Ranges (RFC 1918)
The Internet Engineering Task Force (IETF) reserved specific blocks of addresses for private networks:
- Class A Range:
10.0.0.0to10.255.255.255(Often used in large corporate networks) - Class B Range:
172.16.0.0to172.31.255.255 - Class C Range:
192.168.0.0to192.168.255.255(Standard for home routers, e.g.,192.168.1.1)
How They Work Together: Network Address Translation (NAT)
When you request a page from your laptop (with a private IP like 192.168.1.15), your router translates that request to use your single public IP. When the web server replies to your public IP, your router translates the destination back to your laptop's private IP. This translation process is called NAT.