Dynamic NAT Using Pools

In this post I will remove my previous NAT entry and create a pool of addresses to use for NAT. I'll be using the network in the diagram below and configuring Router1.





First I'll remove the previous NAT (from my last post) configuration.


router1(config)#no ip nat inside source list NAT interface Ethernet0 overload
Dynamic mapping in use, do you want to delete all entries? [no]: yes


After removing the config I verify that I cannot access the internet or ping the internet from the Win7 host.

Now I create a NAT pool with three addresses.


router1(config)#ip nat pool NAT_POOL 10.0.1.250 10.0.1.252 netmask 255.255.255.0


I already have the NAT access-list created from my previous post so I'll use that again.


router1(config)#ip nat inside source list NAT pool NAT_POOL overload


Now I access the internet from the Win7 host and verify that I am being NAT'd.


router1#sh ip nat translations 
Pro Inside global Inside local Outside local Outside global
tcp 10.0.1.251:1231 10.0.2.1:1231 208.43.202.17:80 208.43.202.17:80


I can also check the NAT statistics.


router1#sh ip nat statistics 
Total active translations: 41 (0 static, 41 dynamic; 41 extended)
Outside interfaces:
Ethernet0
Inside interfaces: 
Ethernet1
Hits: 24714 Misses: 1339
CEF Translated packets: 25094, CEF Punted packets: 1907
Expired translations: 1666
Dynamic mappings:
-- Inside Source
[Id: 3] access-list NAT pool NAT_POOL refcount 41
pool NAT_POOL: netmask 255.255.255.0
start 10.0.1.250 end 10.0.1.252
type generic, total addresses 3, allocated 1 (33%), misses 0
Queued Packets: 0