Network address translation (NAT) is a process used in computer networks that allows private IP addresses to be translated into a public IP address. Public IP addresses are limited and in most cases most businesses will only have one public IP address assigned to them. For this reason they need to use NAT in order to translate a private IP address into a public IP address.

Static NAT allows the router translate one-to-one translations of inside local addresses to outside global address. When using static NAT the router assigns addresses on a one-to-one basis, so you will need an equal number of public addresses as private addresses.

This lab is a simple Static NAT lab, that translate one private IP to one public IP address.

Task 1:
Configure the host name on both the router and switch. 

Router>enable
Router#configure terminal
Router(config)#hostname R1
R1(config)#

Task 2:
Set the IP address to the inside and outside interfaces. 

R1(config)#interface ethernet 0/0
R1(config-if)#ip address 192.168.0.254 255.255.255.0
R1(config-if)#no shutdown
R1(config-if)#exit
R1(config)#interface ethernet 0/1
R1(config-if)#ip address 199.100.25.1 255.255.255.248
R1(config-if)#no shutdown
R1(config-if)#exit

Task 3:
Configure the host name and assign the IP address to PC-1 . Ping the gateway to confirm the connectivity.

VPCS>  set pcname PC-1

PC-1> ip 192.168.0.1 /24 192.168.0.254
Checking for duplicate address...
PC1 : 192.168.0.1 255.255.255.0 gateway 192.168.0.254

PC-1> ping 192.168.0.254

84 bytes from 192.168.0.254 icmp_seq=1 ttl=255 time=0.480 ms
84 bytes from 192.168.0.254 icmp_seq=2 ttl=255 time=0.639 ms
84 bytes from 192.168.0.254 icmp_seq=3 ttl=255 time=0.693 ms
84 bytes from 192.168.0.254 icmp_seq=4 ttl=255 time=0.862 ms
84 bytes from 192.168.0.254 icmp_seq=5 ttl=255 time=0.658 ms

Task 4:
Configure the host name and assign the IP address to the Web server. Ping the gateway to confirm the connectivity.

VPCS> set pcname Web
Web> ip 199.100.25.6 /29 199.100.25.1
Checking for duplicate address...
PC1 : 199.100.25.6 255.255.255.248 gateway 199.100.25.1

Web> ping 199.100.25.1

84 bytes from 199.100.25.1 icmp_seq=1 ttl=255 time=0.417 ms
84 bytes from 199.100.25.1 icmp_seq=2 ttl=255 time=0.511 ms
84 bytes from 199.100.25.1 icmp_seq=3 ttl=255 time=0.528 ms
84 bytes from 199.100.25.1 icmp_seq=4 ttl=255 time=0.519 ms
84 bytes from 199.100.25.1 icmp_seq=5 ttl=255 time=0.502 ms

Task 5:
Configure the inside and outside NAT interfaces.

R1(config)#interface ethernet 0/0
R1(config-if)#ip nat inside
R1(config-if)#exit
R1(config)#interface ethernet 0/1
R1(config-if)#ip nat outside
R1(config-if)#exit

Task 6:
Configure the static NAT rule.

R1(config)#ip nat inside source static 192.168.0.1 199.100.25.1

Task 7:
Verify the NAT translation on the router.

R1#show ip nat translations
Pro Inside global      Inside local       Outside local      Outside global
--- 199.100.25.1       192.168.0.1        ---                ---

Task 8:
Ping from PC-1 to the Web server. Afterwards, return back to the router and run the command ‘show ip nat statistics’.

PC-1> ping 199.100.25.6

84 bytes from 199.100.25.6 icmp_seq=1 ttl=63 time=0.909 ms
84 bytes from 199.100.25.6 icmp_seq=2 ttl=63 time=0.841 ms
84 bytes from 199.100.25.6 icmp_seq=3 ttl=63 time=1.166 ms
84 bytes from 199.100.25.6 icmp_seq=4 ttl=63 time=0.889 ms
84 bytes from 199.100.25.6 icmp_seq=5 ttl=63 time=0.883 ms


R1#show ip nat statistics
Total active translations: 1 (1 static, 0 dynamic; 0 extended)
Peak translations: 1, occurred 01:05:01 ago
Outside interfaces:
  Ethernet0/1
Inside interfaces:
  Ethernet0/0
Hits: 0  Misses: 0
CEF Translated packets: 0, CEF Punted packets: 0
Expired translations: 0
Dynamic mappings:

Total doors: 0
Appl doors: 0
Normal doors: 0
Queued Packets: 0
R1#show ip nat statistics
Total active translations: 6 (1 static, 5 dynamic; 5 extended)
Peak translations: 6, occurred 00:00:07 ago
Outside interfaces:
  Ethernet0/1
Inside interfaces:
  Ethernet0/0
Hits: 10  Misses: 0
CEF Translated packets: 10, CEF Punted packets: 0
Expired translations: 0
Dynamic mappings:

Total doors: 0
Appl doors: 0
Normal doors: 0
Queued Packets: 0

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