I have two sites that I need to create a L2 bridge to allow both sites to share the same subnet. There is a limitation with the access control system the client has and we need to be able to extend the subnet. I believe I understand the concept, but continue to have one issue or another.
Here is what we have.
Site #1 (main site) - 10.2.10.1/24
This will be the primary site that handles DHCP and has the controllers for the access control doors.
Site #2 (secondary) - 192.168.1.1/24
This site needs to be able to receive DHCP from site one and communicate on 10.2.10.1/24
I have currently a linux device (sbc) at each site. They are set to forward traffic and the ZT network is configured with 192.168.168.0/24. When I’m on the ZT network, I’m able to communicate with both sites.
I did try to follow the L2 Bridge document. However, it appears that isn’t quite what we are trying to do, but similar.
Not new to this, but clearly I’m overthinking this. Any help would be appriciated.
At a glance, the problem is that your secondary site still has a local DHCP server that is giving out IP addresses for the 192.168.1.0/24 subnet. So even if there’s an L2 link between the sites, they don’t have IP’s in the range that you want (10.2.10.0/24) so they can’t talk to anyone in that range.
Given what you’ve described, I think that what you want to do is setup both sites with their own DHCP servers, but serving a specific range in the same subnet and the L2 link allows cross site communication as if you’re on the same set of switches.
Also this way you can set the default gateway on each site to their local router. Something like:
Site 1:
Router: 10.2.10.1 (default gateway)
DHCP range 10.2.10.50-99
Site 2:
Router: 10.2.10.254 (default gateway)
DHCP range 10.2.10.100-149
If there’s a fixed set of machines on Site 2 that need access you can manually assign a secondary address in the 10.2.10.0/24 subnet to those machines, but if you want the whole thing to be automatic, putting both of them on the same subnet makes more sense.