Public IP Address vs. Private IP Address — What's the Difference?
Edited by Tayyaba Rehman — By Urooj Arif — Published on May 22, 2024
Public IP addresses are unique across the internet, allowing global communication, whereas private IP addresses are reused in multiple networks, suitable for internal network communication only.
Difference Between Public IP Address and Private IP Address
Table of Contents
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Key Differences
Public IP addresses are assigned by Internet Service Providers (ISP) and are used to identify devices on the internet uniquely. They ensure that data sent over the internet reaches the correct destination. Public IPs are essential for accessing the internet and are visible to any device across the global network.
Private IP addresses, on the other hand, are used within private networks and are not unique across the entire internet. These addresses allow multiple devices to communicate within the same network without exposing them directly to the internet. Private IPs are typically assigned by a network router or a server using DHCP (Dynamic Host Configuration Protocol).
The range of private IP addresses is defined by specific blocks reserved for private use, as outlined in the IPv4 and IPv6 standards. These addresses cannot be routed on the internet, ensuring that private networks can use them without conflict or need for coordination with an ISP.
A device within a private network usually accesses the internet through a router. The router uses Network Address Translation (NAT) to translate the private IP address of the device to a public IP address for internet communication, allowing for multiple devices to share a single public IP.
The allocation of public and private IP addresses follows different guidelines and purposes. Public IPs are scarce and managed globally, while private IPs are freely available and managed within private networks. This distinction ensures efficient use of IP addresses while maintaining the functionality and security of network communications.
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Comparison Chart
Uniqueness
Unique globally
Reused across different networks
Assignment
By ISPs for internet access
By network administrators for internal networks
Visibility
Across the entire internet
Only within a private network
Purpose
Enables devices to communicate on the internet
Facilitates communication within a private network
NAT (Network Address Translation)
Not needed for direct internet access
Required for internet access
Compare with Definitions
Public IP Address
Visible to any device across the internet, facilitating global data exchange.
Websites have public IPs that allow users worldwide to access them.
Private IP Address
An IP address used within private networks, not unique globally.
Most home networks use private IPs for devices connected to the router.
Public IP Address
Essential for hosting servers accessible over the internet.
Public IPs are used for hosting web servers that provide content globally.
Private IP Address
Not routable on the internet, requiring NAT for external communication.
Devices with private IPs access the internet through their router’s public IP.
Public IP Address
Managed and distributed by global authorities to prevent duplication.
The Internet Assigned Numbers Authority (IANA) oversees public IP address allocation.
Private IP Address
Allows for extensive reuse in multiple networks without conflict.
Private IPs are reused in offices and homes without affecting each other's networks.
Public IP Address
A globally unique IP address assigned by ISPs for internet communication.
Your home's router uses a public IP to connect to the internet.
Private IP Address
Assigned by network routers or manually by administrators.
Your printer likely has a private IP assigned by your home router.
Public IP Address
Directly routable on the internet, without requiring NAT.
A device with a public IP can send and receive data directly with other devices on the internet.
Private IP Address
Follows specific IP ranges reserved for private use.
192.168.x.x is a common private IP address range.
Common Curiosities
How does a device with a private IP address access the internet?
Through a router using NAT, which translates private IP addresses to a public IP address.
Can a device have both a public and a private IP address?
Yes, devices within a private network have a private IP for internal communication and use the router’s public IP for internet access.
Why are private IP addresses not unique?
Because they are meant for internal network use only, allowing for their reuse in multiple private networks.
How is a public IP address obtained?
Public IP addresses are obtained from ISPs and are essential for accessing the internet.
Can a private IP address be used on the internet?
No, private IP addresses are not routable on the internet and require NAT for external communication.
What is a public IP address?
A public IP address is a unique identifier assigned to a device for communication over the internet.
What are the ranges of private IP addresses?
For IPv4, common ranges include 10.x.x.x, 172.16.x.x to 172.31.x.x, and 192.168.x.x.
Why is NAT necessary for private IP addresses?
NAT translates private IP addresses to a public one for internet communication, allowing multiple devices to share a single public IP.
What happens if two devices on the internet have the same public IP address?
Each device on the internet must have a unique public IP address; duplication can cause data routing errors.
Are public IP addresses safe to use?
While necessary for internet access, public IP addresses can expose devices to security risks if not properly protected with firewalls and security protocols.
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Written by
Urooj ArifUrooj is a skilled content writer at Ask Difference, known for her exceptional ability to simplify complex topics into engaging and informative content. With a passion for research and a flair for clear, concise writing, she consistently delivers articles that resonate with our diverse audience.
Edited by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
