Port Address Translation (overload)

Port Address Translation (overload)

Syntax to implement NAT on Router

Syntax:

Router(config)#interface <type> <no>

Router(config-if)#ip NAT inside

This command need to be given on interface where LAN (Private) Network is present

Router(config-if)#ip NAT outside

This command need to be given on interface where WAN (Public) Network is present

Syntax for configuring PAT is as Follows :

Syntax:

Router(config)#ip nat inside source list <ACL-NO> <Pubiic IP / interface <type> <No> > [overload]

Configuration of PAT:

Mumbai#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Mumbai(config)#
Mumbai(config)#interface serial 0/0/1
Mumbai(config-if)#ip address 201.1.0.15 255.255.255.248
Mumbai(config-if)#no shut
%LINK-5-CHANGED: Interface Serial0/0/1, changed state to up
Mumbai(config-if)#encapsulation ppp 
Mumbai(config-if)#ip nat outside 
Mumbai(config-if)#exit
Mumbai(config)#interface fastEthernet 0/0
Mumbai(config-if)#ip nat inside 
Mumbai(config-if)#exit
Mumbai(config)#
Mumbai(config)#access-list 10 permit 192.168.2.0 0.0.0.255
Mumbai(config)#ip nat inside source list 10 interface serial 0/0/1 overload 
Mumbai(config)#end
Mumbai#

Show command:

Mumbai#sh ip nat translation

Mumbai#debug ip nat

Verify the output using following commands:

OUTPUT:

Mumbai#sh ip nat translations

Verify the output using following commands

To verify the output:

Output:

Mumbai#show ip nat translation


Output:

ROUTER#sh ip nat translations

Pro          Inside global         Inside local              Outside local             Outside global

tcp         201.1.0.15:4965    192.168.2.10:4965    82.204.219.231:21      82.204.219.23!1:21

tcp         201.1.0.15:4973    192.168.2.10:4973    64.12.171.246:25        64.12.171.246:25

tcp         201.1.0.15:4974    192.168.2.10:4974    82.204.219.231:21      82.204.219.231:21

tcp         201.1.0.15:53955  192.168.2.10:53955   64.4.52.182:80           64.4.52.182:80

tcp         201.1.0.15:53958  192.168.2.10:53958   207.46.208.105:80      207.46.208.105:80

tcp         201.1.0.15:53961  192.168.2.10:53961  207.46.208.105:80       207.46.208.105:80


To enable Debug on NAT:

Router#debug ip nat

Mumbai#debug ip nat 

IP NAT debugging is on