LAN across routers

[chpalmer]

I have a set of devices that will only work (communicate with each other) on a local LAN.  I want to place one device out on a remote site (behind router A) which crosses a few networks (all VPN and private) to get to the device on the other end (behind router Z) on the same subnet..

Possible scenario?

[Derelict]

If it is an absolute requirement and cannot be routed, probably a TAP-mode OpenVPN.

I don't see anything on the docs wiki but there is something in the book:

https://portal.pfsense.org/docs/book/openvpn/bridged-openvpn-connections.html

[chpalmer]

@Derelict:

If it is an absolute requirement and cannot be routed, probably a TAP-mode OpenVPN.

Thanks good read!  I may try an experiment this weekend.

[johnpoz]

"I have a set of devices that will only work (communicate with each other) on a local LAN."

Why?  Do they not have the ability to set a gateway?  Do they use some sort of L2 only protocol?

You can create a TAP connection in openvpn… But maybe the requirement is not same layer2 or no gateway but latency issue?  What are these devices and we can dig a bit deeper, etc.

[chpalmer]

@johnpoz:

Why?  Do they not have the ability to set a gateway?  Do they use some sort of L2 only protocol?
What are these devices and we can dig a bit deeper, etc.

Im digging a little bit myself as Im not sure the "proposing" engineer is correct based on a document I looked at..

These are a VOIP style device that transport radio audio between radio systems and dispatch consoles.  Due to NDA I have to withhold brand and model till I find out more what I can and can't do..  But I believe its a lack of gateway issue if it actually really exists.

But the VPN via tap helps me with my argument..  ;)

[johnpoz]

transmitting audio is going to come into a latency issue as well..  This remote site is how far away connected how?

And this traffic is going to flow over other VPNs?  You mention networks.. So your going to tunnel inside a tunnel - not the most efficient mode of travel ;)  And your talking voice which is small - but are you talking udp I would assume for the voice transmit - are you going to put that inside any tcp vpn tunnel?

[chpalmer]

@johnpoz:

This remote site is how far away connected how?

The existing network was at the time it was built the largest private VOIP type network in the world.  Its radio audio so one way at a time generally. Latency is not as big an issue as two way audio would be.

Makes use of microwave, fiber and even some t-1's thrown in for good measure.

The new proposed equipment was said to be unable to span subnets but Ive since found a document that says otherwise. So this is a non issue. But it does raise my eyebrows about the quality of people we were sent..

:o