IP Routing - 2 Unique Ranges on same VLAN ID - Only 1 Gateway

[Steve21]

Good Evening All, 

We've found that one schools have a VLAN with 2 different IP ranges being used on it. Obviously only one of these is effectively getting to the gateway to get off the VLAN.

Is there any way to specify separate gateways on a single vlan ID for the two ranges?

As a quick example

10.0.1.X range 
10.1.X.X range 

Both on ID1 with the Gateway on the core going to 10.0.1.254 meaning the 10.1.x.x range isn't getting anywhere. Looking to nuke the whole setup shortly so happy with any short-term fixes, but just wondering if there's a way to get the two to talk temporarily without changing all the devices settings manually? Did consider seeing what would happen if we just massively increase the Gateways subnet on the core to cover both ranges, but this would also go over multiple other VLANs too so isn't ideal

Many thanks,

Steve

[Aprice]

Some kit might support adding a second IP to the same VLAN interface (known as multinetting)

As you say anything you do here should be temporary, it's not a good solution!

You could add a router onto the network with 2 ethernet interfaces, one interface with an IP in 10.0.1.x and the other in 10.1.x.x. the existing router on the network will need a static route to get to the other network via this new routers IP. And the new router a default route via the existing router.

 

 

[Steve21]

Aye that's an idea - I do wonder if you could do a similar principle with just adding extra VLANs to the current core to replicate that principle. 

Yep definitely want to nuke it all, but you know there will always be that one hidden device that a specific outdated system is built on-top of that will break everything if it's not routing, so hoping to have a fallback option at least till they all get rebuilt

Steve