products:ict:communications:courses:cisco:ccna:public_vs_private_ip_addresses
Public and private IP addresses are two categories of IP addresses used in networking, each serving different purposes and operating within distinct address ranges. Here's an overview of public and private IP addresses:
1. Public IP Addresses:
- Public IP addresses are globally unique and routable on the Internet.
- They are assigned by regional Internet registries (such as ARIN, RIPE, and APNIC) to organizations and ISPs.
- Public IP addresses allow devices to communicate with other devices on the Internet.
- They are used for hosting web servers, email servers, and other services accessible from the Internet.
- Public IP addresses are limited in number and are a valuable resource in the IPv4 address space.
2. Private IP Addresses:
- Private IP addresses are reserved for use within private networks and are not routable on the Internet.
- They are defined in RFC 1918 and provide a mechanism for conserving public IP address space.
- Private IP addresses can be reused within multiple private networks without conflict.
- Devices within the same private network can communicate with each other using private IP addresses.
- Private IP addresses are commonly used in homes, businesses, and organizations to facilitate internal communication and network connectivity.
3. Address Ranges:
- Private IP addresses are assigned from three blocks of IP address ranges reserved for private use:
- Class A: 10.0.0.0 to 10.255.255.255 (10.0.0.0/8)
- Class B: 172.16.0.0 to 172.31.255.255 (172.16.0.0/12)
- Class C: 192.168.0.0 to 192.168.255.255 (192.168.0.0/16)
- Public IP addresses can be assigned from any range of IP addresses not reserved for private use.
4. NAT (Network Address Translation):
- NAT is a technique used to translate private IP addresses to public IP addresses and vice versa.
- NAT allows multiple devices within a private network to share a single public IP address for accessing the Internet.
- It helps conserve public IP address space and provides an additional layer of security by hiding internal IP addresses from external networks.
In summary, public IP addresses are used for devices that need to communicate over the Internet, while private IP addresses are used for internal communication within private networks. NAT is commonly used to facilitate communication between private and public networks while conserving public IP address space.
products/ict/communications/courses/cisco/ccna/public_vs_private_ip_addresses.txt · Last modified: 2024/03/31 23:12 by wikiadmin