Dumb (?) Routing Question

[ANiceEnglishman]

Scenario as follows

We have a curriculum network and a completely separate Admin network. The Admin network is actually part of the Council's city-wide network and talks to the rest of the city via a WAN link.

We have installed a new server (to run a new MIS system) on the curriculum network. Let's say the IP address is 192.168.1.249. Workstations on our bit of the Admin network (only) need to talk to the server to access the MIS system.

The Council's network guys are struggling to achieve this as both networks use the 192.168.1.x address range.

I am no network expert but isn't it possible to configure a router to say "Ah, here's a packet for 192.168.1.249 (or for MIS_SERVER). Send it to the curriculum network rather than up the WAN link" ?

Any ideas / comments from networking experts welcome.

[ChrisH]

So your saying you have physically seperate networks for admin and curric but they both use the 192.168.1.X range and meet at a router?

[Geoff]

yep. you need a route with a /32 netmask (single host). The way to do this in Linux (for example) would be:

eth0 = admin network ip 192.168.1.2
eth1 = curriculum network ip 192.168.1.1

route add 192.168.1.249/32 gw 192.168.1.1 dev eth1

You could use the gw or the dev options and it would still figure it out but its good to be specific.

Obviously the implementation will differ depending on the router being used but really, this is networking 101. Your council guys are clueless and you should be worried.

[CyberNerd]

assuming the 192.168.1.x network isn't already subnetted.
Its conceivable that the two networks have different subnet masks -if they are the same, take Geoff's advice and worry.

[ANiceEnglishman]

Thanks for all the info so far. I'll try to reciprocate when someting comes up I know about.

Curric subnet mask is 255.255.254.0

I forgot to mention that as preparation for this exercise they changed all the workstations from DHCP to static IP's. Looked at one and it's

IP 172.20.208.84

subnet mask 255.255.255.0

I presume their remarks about the same IP adfress range was referring to the wider network.

And, yes, we have two physically seperate networks that meet at a router

[budgester]

Sounds like judicious use of a cluebat is needed.