Setting Static NAT and PAT - tmansfield42/Tech-Journal GitHub Wiki

In order to configure Static NAT and PAT it's important to understand how NAT and PAT are used in a network.

NAT masquerades our private (local) ip addresses such as 192.168.1.2 and 192.168.1.3 to one public facing IP address, it uses a NAT table to keep track of the translations it makes, but basically it allows clients to share one public IP address.

NAT, used in tandem with PAT gives a source TCP port to the outgoing (local->open internet) packets so it can keep track of where packets should be routed to that come from the open internet.

The goal is to configure Static NAT on a router to translate the web server's IP 10.0.0.2 to 50.0.0.1.

you can do this by running the following CLI inputs for Router 1:

enable
configure terminal
hostname R1
interface fastethernet 0/0
ip address 10.0.0.1 255.0.0.0
no shutdown
exit
interface serial 0/0/0
ip address 20.0.0.2 255.0.0.0
no shutdown
exit

Router 0:

enable
configure terminal
hostname R0
interface fastethernet 0/0
ip address 30.0.0.1 255.0.0.0
no shutdown
exit
interface serial 0/0/0
ip address 20.0.0.1 255.0.0.0
clock rate 64000
bandwidth 64
no shutdown
exit

On router 1:

ip route 30.0.0.0 255.0.0.0 20.0.0.1

Router 0:

ip route 50.0.0.0 255.0.0.0 20.0.0.2

Static NAT on Router 1:

interface fastEthernet 0/0
ip nat inside
exit
interface serial 0/0/0
ip nat outside
exit

Router 1 Static Rule:

ip nat inside source static 10.0.0.2 50.0.0.1

To configure PAT:

ip nat pool <Name1> <startIP> <endIP> netmask 255.0.0.0

access-list 1 permit <internalIP> 0.0.0.255

ip nat inside source list 1 pool <Name1> overload