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Webcast-Catalyst9k
New Member

LAST QUESTION ON NAT

Dear All,

I was reading my NAT Design Paper, because I am going to Implement NAT in My Company.

Now, I want to ask you for only the Process of Static NAT , to allow External Users ? on internet side ? to ? access a specific server inside my LAN.

Which is the things that determine this NAT will Work from External to Internal , or Internal to External ?

Please answer the 3 questions .

1- Is it the Route command that I configured on the router it self , only ?

Or,

2- Is it the Route Command + NAT Table which is configured on the Router it self ?

Because As far as I know, I understood the following:-

To configure the NAT, I have to:-

1- determine which INTERFACE will act as IP NAT OUTSIDE , usually the one which have the IP from the ISP Side.

2- Determine which INTERFACE will act as IP NAT INSIDE , usually the one which have the IP from the Private LAN.

3- Determine the NAT statement , if its STATIC / dynamic /overloading .

4- Determine the Route command .

3- Here is Step 4 , I can make rule to forward every thing from INTERNAL to EXTERNAL or from EXTERNAL to INTERNAL , according to My Design Requirements.

So, from the NAT Command + Route Command , I can make the NAT From External to Internal , or, from Internal to External . is that correct ?

1 REPLY
New Member

Re: LAST QUESTION ON NAT

Hi,

NAT works as follows:

When the packet hits outside interface, router will check the NAT translation table and if there is any matching entry then the NATting will be performed, after which the routing check will be done and packet will be routed.

When the packet hits inside interface, router will check the routing table first and if the packet has to go out from the NAT outside interface then the NATting will be performed before forwarding the packet.

HTH.

Hitesh / Mohit

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