I have a device with fixed IP address (192.168.1.86). I also have a DHCP network using 192.168.1.x--and I'm not allowed to just reserve 192.168.1.86 on that network. I have one machine (call it a bridge) that needs to be able to talk to both the main network, and that one fixed-address device.
A has two network adapters, so what I've done so far is configure one interface with DHCP to talk to the main network, and the other manually to talk to the fixed-address device. Then I enable one interface and disable the other, so at any given time I can talk to one or other other. This is obviously pretty clumsy and sometimes frustrating though.
I'd like would be to manage to do this without manually enabling/disabling the interfaces, but having all traffic destined for 192.168.1.86 automatically get sent to one interface, and traffic for any other address get sent by the other interface. And yes, I realize that if I can manage to do this, that bridge machine won't be able to talk to 192.168.1.86 on the main network any more--I'm fine with that. As a bonus, it would also be nice if I could get the fixed-address device to talk to the internet via the bridge machine.
This seems like it ought to be a static route, but I'm not sure how (or even if it's possible) to set up a static route for one specific address rather than an entire subnet (especially when that address is inside the subnet otherwise handled by the other interface).
So, can I (and if so how can I) configure the bridge machine to send traffic specifically for 192.168.1.86 to one interface, and traffic for any other address to the other interface?
The bridge machine (the one connected to both the rest of the network and the fixed-address device) is running CentOS 7.