NAT

NAT stands for the Network Address Translation in computer networking. It is basically a process of adjusting the network address information in datagram (IP) packet headers and also in transit across a traffic routing device for the purpose of remapping some given address space into another.

Generally now a day’s NAT is used in conjunction with network masquerading which is a camouflage technique that conceals a complete address space, which usually contains addresses of private network, behind a single internet protocol address in mostly public address space.

This procedure is executed in a routing device that utilizes stateful translation tables to map the hidden addresses into a single address and then after that redraft the outgoing Internet Protocol (IP) packets on exit so that they appear to initiate from the router. In the reverse communications path the originating IP addresses are responded back using some of the rules stored in the translation table. The translation table rules are made in this way that they are swilled out after short period of time without new traffic refreshing their state.

As mentioned above this method allows communication through the routers only and only if the conversation initiates in the masqueraded network, as this establishes the translation table. So a web browser which is included in a masqueraded network can browse a website which is outside but a web browser outside the network cannot simply browse a website which is in the network. Now a day’s many of the NAT devices enable the network administrator to configure translation table entries for their permanent use. This unique feature is mostly known as the “static NAT” or port forwarding and allows traffic initiated in the outside network to reach the concerning host inside the masqueraded network. Now because of the increasing popularity of this method it is also known as IP masquerading.