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 10.0.0.6) and it is configured in the application to that IP. We are outsourcing this server (say

192.168.1.2) via a dedicated link handled by a small Cisco 1700 (with an IP of 10.0.0.240) router that is physically located at our location that they manage.

Currently my internal routers are set to route all other traffic destined for 192.168.1.2 via 10.0.0.240 and then it winds its way onto the new server which works. (they have the statement: "ip route

192.168.1.2 255.255.255.255 10.0.0.240")

I need to come up with a way to redirect the traffic destined for

10.0.0.6 coming from this front-end to the IP 192.168.1.2 and so that it goes out via 10.0.0.240 without manually touching each machine and changing it to point to 192.168.1.2.

I had tried a route statement of "ip route 10.0.0.6 255.255.255.255

192.168.1.2" but that results in a loop where the traffic just bounces around on the router since there is no 10.0.0.6 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

Reply to
dxt178
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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

10.0.0.6 now to an address of 192.168.1.2.

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

original design:

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

10.0.0.0/24 10.0.0.6/24

New Design

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

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

10.0.0.0/24 10.0.0.0/24 192.168.1.0/24 192.168.1.2

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

10.0.0.6 which would then be NATted to 192.168.1.2, this might work. It would depend > Currently our users rely on a front-end that is pointing to a server
Reply to
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 10.0.0.6 traffic to 192.168.1.2 then the existing IP route on my side pointing that traffic to 10.0.0.240 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

192.168.1.2 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

Reply to
dxt178

If client 10.0.0.27 with netmask of 255.0.0.0 attempts to connect to

10.0.0.6, it expects 10.0.0.6 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 10.0.0.6, then the client will declare a failure to reach 10.0.0.6.

So you would have to configure your router to somehow respond to ARP requests for 10.0.0.6 as well as its own address, or artificially inject ARP entries in each client to point 10.0.0.6 to the router.

Not sure if this would work, but adding static routes in each client might be able to force 10.0.0.6 to be routed to the router instead of being handled as an IP in the same subnet.

Reply to
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 10.0.0.27 with netmask of 255.0.0.0 attempts to connect to

Reply to
dxt178

Your individial PCs will not send be sending packets to the router if they think that 10.0.0.6 is part of their local subnet.

You'll have to get your router to answer to ARP requests for 10.0.0.6 for this to work. Not sure if it is legal, but if you create an interface with ip 10.0.0.6/32 , 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.

Reply to
JF Mezei

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