Chapter30 More About....
More About NAT
30-14
Cisco Router and Security Device Manager Version 2.2 Users Guide
OL-4015-08
Scenario 2
You need to map each IP address in a network to a unique public IP address, and
you do not want to create a separate rule for each mapping. The source network
number is 10.l2.12.0, and the target network is 172.17.4.0. However, in this
scenario, it is not necessary to know the source or target network numbers. It is
sufficient to enter host addresses and a network mask.
The following table shows how the fields in the Add Address Translation Rule
window would be used.
Result
NAT derives the Translate from network address from the host IP address and
the subnet mask. NAT derives the Translate to network address from the the net
mask entered in the Translate from fields, and the Translate to IP address. The
source IP address in any packet leaving the original network is translated to an
address in the 172.17.4.0 network.
Scenario 3
You want to use the same global IP address for several hosts on the trusted
network. Inbound traffic will contain a different port number based on the
destination host.
The following table shows how the fields in the Add Address Translation Rule
window would be used.
Static/Dynamic
Translate from Interface Fields Translate to Interface Fields
IP Address Net Mask IP Address Redirect Port
Static 10.12.12.35 (host) 255.255.255.0 172.17.4.8 (host) Leave unchecked.
Static/Dynamic
Translate from... fields Translate to... fields
IP Address Net Mask IP Address Redirect Port
Static 10.12.12.3 Leave blank 172.17.4.8 UDP
Original Port 137
Translated Port 139