How do I forward/handle this routing change?

Currently our users rely on a front-end that is pointing to a server that resides inside of our lan (say and it is configured in the application to that IP. We are outsourcing this server (say via a dedicated link handled by a small Cisco 1700 (with an IP of router that is physically located at our location that they manage.

Currently my internal routers are set to route all other traffic destined for via and then it winds its way onto the new server which works. (they have the statement: "ip route")

I need to come up with a way to redirect the traffic destined for coming from this front-end to the IP and so that it goes out via without manually touching each machine and changing it to point to

I had tried a route statement of "ip route" but that results in a loop where the traffic just bounces around on the router since there is no on their side.

Should I just have them put a route in their router to then handle forwarding that traffic on to their server, or is there a way for me to handle this all on my side of the network so no changes need to be made on their router?

Thanks, Dominic

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I believe you are correct in that specifying a static route to a destination that does not exist and is not known on the next hop router could create a routing loop.

If I understand this correctly, you are attempting to redirect traffic which all your PCs using this application used to send to an address of now to an address of

Have you considered setting up a Network Address Translation? From what I'm understanding here, you have the following design:

original design:

======== ----> ========= PCs server

New Design

======== ========= ----> =========== ------>

============ PCs your router provider router server

If you were to instead, on the router you use to communicate with your outsourcing company's Cisco 1700 router, set up a Network address translation, so that your 10.0.0.x machines would send packets to which would then be NATted to, this might work. It would depend > Currently our users rely on a front-end that is pointing to a server
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Mike Rahl

Amazingly you did understand my question quite well :) NAT may be a possibility, I wasn't thinking in that direction because I was aproaching it solely as a routing problem. I kind of don't understand your last bit about the server originally being on the same subnet or not... if you'd have a second to explain that to me I'd appreciate it.

If I NAT traffic to then the existing IP route on my side pointing that traffic to would stay and work fine. They would not need to update their router because when the traffic hits it it appears just as the rest of the traffic destined for that already routes fine.

That sounds like a valid plan, I'm going to test it out now.

Thanks! Dom> I believe you are correct in that specifying a static route to a

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If client with netmask of attempts to connect to, it expects to be located in the same LAN and will send out ARP packets to try to find its ethernet address and communicate locally. If there is nobody to respond to ARP requests for, then the client will declare a failure to reach

So you would have to configure your router to somehow respond to ARP requests for as well as its own address, or artificially inject ARP entries in each client to point to the router.

Not sure if this would work, but adding static routes in each client might be able to force to be routed to the router instead of being handled as an IP in the same subnet.

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JF Mezei

Ahh, I see what your saying... but I guess how I get lucky with this one is that the router containing the route statements I mentioned is also the default gateway for all the individual PC's. I believe that is why.

I was attempting to set up NAT but it appears the IOS (11.3) version of this router doesn't support it. It allowed me to define "ip nat inside" but when I tried to add "ip nat inside source static..." it gave an error at the word static... so i'm guessing the older IOS has a different syntax. (?)

Dom> dxt178 wrote:

client with netmask of attempts to connect to

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Your individial PCs will not send be sending packets to the router if they think that is part of their local subnet.

You'll have to get your router to answer to ARP requests for for this to work. Not sure if it is legal, but if you create an interface with ip , that would cause the router to reply to ARP requests for that IP. But it might conflict with the router's real IP for that subnet.

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