One-To-One Nat With Port Translation - HP 7102dl - ProCurve Secure Router Configuration Manual

Configuring Network Address Translation
NAT Services on the ProCurve Secure Router
6-6
Edge switch
Edge switch
Core switch
Web
server
192.168.1.2
Figure 6-3. One-to-One NAT for Inbound Traffic
Again, the Secure Router OS firewall records information about the packets
it NATs in its port-mapping table. When the internal server replies to a request,
the Secure Router OS firewall changes the packet's source address—the
server's private IP address—to the server's public IP address.
For example, when the Web server shown in Figure 6-3 sends replies to clients,
the return packets have the source address of 192.168.1.2—the Web server's
private IP address. To conceal this address from Internet users, the Secure
Router OS firewall NATs the source address, changing it from 192.168.1.2 to
10.10.10.1.

One-to-One NAT with Port Translation

The Secure Router OS firewall also supports port translation for one-to-one
NAT. With port translation, the Secure Router OS firewall can forward traffic
to a device on the internal network using the port you specify.
Port translation allows two or more devices on the internal network to share
one IP address. For example, the Secure Router OS firewall can translate the
destination IP addresses of all traffic destined to port 80 to one private IP
address, and it can translate the destination IP addresses of all traffic destined
to port 21 to another private address. When the Secure Router OS firewall
2) NAT destination
address on incoming
requests for Web
server to 192.168.1.2
ProCurve Secure
Router
3) NAT source
address on
replies that
Web server
sends (change
to 10.10.10.1)
1 Internet
user sends
request to
Web server
at 10.10.10.1
Internet