IP Forwarding (Is there any way to do what this intention is)

[xaeniac]

Basically I have a home baked application IP information is :

IP : 192.168.0.2/24

GW:192.168.0.1

DestinationIP:192.168.0.3

Basically these ip settings are hardcoded and can not change.  The .3 does not exist on the network.  Is there a way to forward any traffic that hits 0.3 to forward to lets say a 192.168.1.3 on a seperate network?  I know its an issue because there is no router involved in communicating on the same subnet.  Is there any Cisco device that could get this accomplished?  This computer is plugged into a 2811 for this scenario. 

[jliscano]

Hi -

I wouldn't call it forwarding but NAT.  Taking the same concept of NAT, you can translate 192.168.0.3 to 192.168.1.3 on your 2811 router (if your IOS is capable of it).  So, if traffic destined to 0.3 is seen on the router, it translates it to 1.3.  You just need to make sure 1.3 exists in the network and can be routed to it.  Here's a link on how configuring NAT: http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094e77.shtml.

Hopefully this will work in your scenario.

Regards.

[xaeniac]

But for NAT to take place does not traffic need to be routed (in other words traffic has to be routed)?  When 192.168.0.2 communicates to 192.168.0.3 no routing takes place.  Can you clarify or respond to this statement.

[jliscano]

Yes, no routing takes place since it's the same subnet but that doesn't mean that your router doesn't have the 0.3 translation in the NAT table in the router.  If 1.3 hits the router it will translate to 0.3.  But your request is reveresed you need 0.3 to translate to 1.3.  Going back to the link I sent you, there is an example of redirecting TCP traffic to another TCP port or address.  The 2nd to the last paragraph shows that they are doing NAT translation within the same subnet, albeit port to port on a physical host.

A shot in the dark but you may be able to do assign a loopback IP  with 0.3 and then do the NAT redirect as I mentioned above giving you a "physical host".

But you should give it a shot since I see no other method in Cisco to do IP forwarding the way you want to do it.

If someone else has a better solution, feel free to chime in.

[cadet alain]

Hi,

Could you explain more what you want to do and why you want to do this.

Regards.

Alain.

[agurtu]

You can use a feature called Policy Based Routing and define which packet should be sent where on the network.