Configuring Static NAT: One Private to One Permanent Public Address Translation


Step 1: Define a static route on the remote router stating where public addresses should be routed.

ISP(config)#ip route 64.64.64.64 255.255.255.255.128 s0/0

Informs the ISP where to send packets with addresses destined for 64.64.64.64 255.255.255.128

Step 2: Create a static mapping on your router that will perform NAT.

Corp(config)#ip nat inside source static 172.16.10.5 64.64.64.65

Permanently translates inside address of 172.16.10.5 to a public address of 64.64.64.65

Use the command for each of the private IP addresses you want to statically map to a public address

Step 3: Define which interfaces are inside (contain the private addresses).

Corp(config)#int fa 0/0

 
 

Corp(config-if)#ip nat inside

You can have more than one inside interface on a router

Step 4: Define the outside interface (the interface leading to the public network).

Corp(config)#int s 0/0

 
 

Corp(config-if)#ip nat outside

Defines which interface is the outside interface for NAT translation


Caution:

Make sure that you have in your router configurations a way for packets to travel back to your NAT router. Include a static route on the ISP router advertising your NAT pool and how to travel back to your internal network. Without this in place, a packet can leave your network with a public address, but will not be able to return if your ISP router does not know where the pool of public addresses exists in the network. You should be advertising the pool of public addresses, not your private addresses.





CCNA Self-Study(c) CCNA Portable Command Guide
CCNA Portable Command Guide
ISBN: 1587201585
EAN: 2147483647
Year: 2006
Pages: 261
Authors: Scott Empson

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