NAT

sho ip nat translations
   Useful:  sho ip nat translations | i ---
sho ip nat statistics

Inside Local  = A private IP in your network like 192.168.88.1
Inside Global  = A public IP which is in your network.
Outside Global  = The destination public IP
Outside Local  =A private IP address referencing an outside device (seen when NAT is used at the destination location).


 

Inside NAT – static

In example your company has a network of 172.0.0.0/16 subnet. A 3rd party site is connected to the network and they do not want to modify their LAN network which has 192.168.88.0/24  subnet configured.

One solution is to configure inside NAT on the gateway:

inside-nat.PNG

 

ip nat inside source static 192.168.88.10 172.0.3.10
!
!Do not forget the "ip nat inside" and "ip nat outside" configurations

 

Routing

The NAT router must have static / dynamic routes to 192.168.88.10. The router also need to advertise the 172.0.3.10 IP to the WAN, so the other sites have routes to the destination network.

Be careful! Do not advertise the inside local subnet (192.168.88.10) to the WAN.

 

Outside NAT – static

 

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