Cisco Systems 78-11741-02 Overloading Inside Global Addresses Example, Translating Overlapping Address Example

Configuring IP Addressing
IP Addressing Examples
IPC-62
Cisco IOS IP Configuration Guide
ip nat inside source route-map provider1-map pool provider1-space
ip nat inside source route-map provider2-map pool providere2-space
!
interface Serial0/0
ip nat outside
!
interface Serial0/1
ip nat outside
!
route-map provider1-map permit 10
match ip address 1
match interface Serial0/0
!
route-map provider2-map permit 10
match ip address 1
match interface Serial0/1
Overloading Inside Global Addresses Example
The following example creates a pool of addresses named net-208. The pool contains addresses from
171.69.233.208 to 171.69.233.223. Access list 1 allows packets having the SA from 192.168.1.0 to
192.168.1.255. If no translation exists, packets matching access list 1 are translated to an address from
the pool. The router allows multiple local addresses (192.168.1.0 to 192.168.1.255) to use the same
global address. The router retains port numbers to differentiate the connections.
ip nat pool net-208 171.69.233.208 171.69.233.223 netmask 255.255.255.240
ip nat inside source list 1 pool net-208 overload
!
interface serial0
ip address 171.69.232.182 255.255.255.240
ip nat outside
!
interface ethernet0
ip address 192.168.1.94 255.255.255.0
ip nat inside
!
access-list 1 permit 192.168.1.0 0.0.0.255
Translating Overlapping Address Example
In the following example, the addresses in the local network are being used legitimately by someone else
on the Internet. An extra translation is required to access that external network. Pool net-10 is a pool of
outside local IP addresses. The statement, ip nat outside source list 1 pool net-10, translates the
addresses of hosts from the outside overlapping network to addresses in that pool.
ip nat pool net-208 171.69.233.208 171.69.233.223 prefix-length 28
ip nat pool net-10 10.0.1.0 10.0.1.255 prefix-length 24
ip nat inside source list 1 pool net-208
ip nat outside source list 1 pool net-10
!
interface serial 0
ip address 171.69.232.192 255.255.255.240
ip nat outside
!
interface ethernet0
ip address 192.168.1.94 255.255.255.0
ip nat inside
!
access-list 1 permit 192.168.1.0 0.0.0.255