NAT - NETWORK ADDRESS TRANSLATION

Advantages :

NAT allows existing addressing schemes to remain in place avoiding the hardships of re-addressing for connectivity requirements to the Internet.

NAT provides security in the sense that the private IP addresses used within the user group will be hidden from the outside world. This will make the job of hacking into a system on a network difficult

The NAT translation represents a level of indirection. Thus, it automatically creates a type of firewall between the organization's network and the public Internet. It is more difficult for any client devices to be accessed directly by someone malicious because the clients don't have publicly-known IP addresses.

Disadvantages :

The advanced application H.323(VoIP Protocol), is a known trouble spot for NAT routers and firewalls.

NAT represents one more complexity in setting up and managing the network. It also makes troubleshooting more confusing due to address substitutions.

Protocols like IPSec are designed to detect modifications to headers and commonly balk at the changes that NAT makes, since they cannot differentiate those changes from malicious datagram “hacking”. It is still possible to combine NAT and IPSec, but this becomes more complicated.

Dats all for now ............