NAT and PAT

[devang_etcom]

i know what is NAT and PAT but how can i define PAT in pure words???it means how to explain differance between NAT and PAT????????

[ankurbhasin]

HI Devang,

When it is NAT it is single lan ip translated to single WAN ip and no way multiple lan ip can be translated to single wan ip address.

When it is PAT it is multiple lan ip which can be translated to single WAN ip address or group of WAN ip address usning the port numbers.

When you use overload statement with your NAT configuration on your cisco routers it is actually doing PATTING which we say as NAT OVERLOAD.

PAT is more widely used as key term with firewalls like Cisco PIX.

HTH

Ankur

[ben.dailey]

NAT = Network Address Translation - IP addresses are translated by a router or firewall as they transverse interfaces. The device maintains a translation table to track translations between addresses

PAT = Port Address Translation - similar concept but instead of IP addresses being translated, port numbers are translated.

In most scenarios you will use a combination of both.