Understanding of Cisco IP NAT

Watching Todd's CCNA study guide recently saw a bit of confusion about NAT conversion. Watched a few heroes after the analysis of the parameters in IP Nat, this side also wrote their own shallow understanding of IP NAT syntax.

See IP nat inside again | Outside Source | Destination list X pool Y, then want to inside/outside what is the difference, source/destination and what role.

Now it's easy to understand:

1:inside representative inside-outside,outside means outside-inside. The direction does not work, it will affect whether the package is routed first or the address is first converted. inside, outside the router-to-package operation is to route and then convert the address first, and outside-Inside is the first to convert the address (external address to internal address) and then route. The purpose of the system is to ensure that routers are accessing intranet addresses within the network;

2:source/Destination This parameter mainly explains which part of the packet Nat conversion is converted, if it is source, it means that the conversion of the package source address;destination is the conversion da;

3:ip nat inside source is equivalent to IP NAT outside destination, which means that if the packet is inside port to the outside port, then the package changes the SA, if the packet from the outside port to the inside port, is to change the packet da;

These are some of the personal summary, there are mistakes please point out ~

This article is from the "Understanding of Nat" blog, so be sure to keep this source http://legendland.blog.51cto.com/2043145/1897444

Understanding of Cisco IP NAT