Public IP Address and Private IP Address in Computer Networks

Public IP Address and Private IP Address in Computer Networks

Public IP Address and Private IP Address

Public Host

Any computer accessing a public network like internet must have a  unique ip address.Such a host is termed as public host. IP address of the public host is termed as public IP address.

 
Private Host

The total IP addresses available  are very limited. So it is not possible to assign unique ip address to all computers in the world. Here comes the importance of private IP address. The following ranges of IP addresses are reserved for private IP.

  • 10.0.0.0         to   10.255.255.255
  • 172.16.0.0     to   172.31.255.255
  • 192.168.0.0   to   192.168.255.255

Inside a LAN or a private network computers can use these ip addresses. Two different private network may use the same set of private IP addresses.


These private hosts can access internet or a public network through a public host.That is the private host's identity will not be visible in the public network, but it shows only the IP address of the public host through which it is connected to the internet. That is Private host shows the IP address of the public host in the Internet environment,but in the local network it shows the private IP address.
 
A private network is typically a network that uses private IP address space.Private IP addresses were originally created due to the shortage of publicly registered IP addresses created by the IPv4 standard.
 
Merging two Private Networks
 
Internal networks  of two different organizations may use the same private IP addresses.Problem occurs when trying to merge two such networks. We may apply the following solutions.
  • One network must renumber
  • A NAT router must be placed between the networks.