Public IP vs Private IP: Understanding Network NAT
Documentation on the technical differences between public facing IP addresses and local private network addressing schemas.
Key Takeaways
- •Public IPs are globally unique and assigned by your ISP.
- •Private IPs are strictly local and assigned by your local router's DHCP server.
- •NAT (Network Address Translation) bridges the gap between private and public IPs.
What is a Public IP?
A Public IP is an externally facing IP address provided by your Internet Service Provider (ISP). This is the address that the rest of the internet sees when you visit a website. It must be completely unique globally.
What is a Private IP?
A Private IP is an address designated strictly for local network use (LAN). Devices like your phone, laptop, and smart TV within your home share the same public IP but have distinct private IPs (commonly within the 192.168.x.x or 10.x.x.x blocks).
The Role of NAT
Network Address Translation (NAT) operates on your router. When your local device requests a web page, the router intercepts the request, replaces your private IP with its public IP, and forwards it to the internet. When the response arrives, the router translates it back to the specific private IP.
Frequently Asked Questions
Are private IP addresses secure?
Private IPs cannot be routed over the public internet, which inherently protects local devices from direct external attacks unless ports are explicitly forwarded.
