I read quite some information about the subject lately – because I’m really not used to work at such “low layers” – but I can’t point the finger on what I’m doing wrong. Believe me, I tried 😉
I would like to connect a cloud server as it was part of our corporate LAN.
I decided to create a layer 2 bridge (br0), the main reason being that I need to receive broadcasted packets from the LAN in order for an appliance to been seen by the cloud server.
I created a route on the cloud server to direct the LAN subnet through the tap0 interface.
ARP table on the LAN client shows the cloud server IP/MAC entry.
I can ping br0 from the cloud and I can ping the cloud machine’s tap0 (statically defined IP in the client subnet) from the LAN client.
When I do a tcpdump on both TAP interfaces, I can seen LAN traffic (STP, IP, ARP, …) flowing.
This is where things cease to be great: I can’t reach other machines on the LAN (when I ping the LAN gateway I get “Destination Host Unreachable”. I’ve got no reply when I do the test with other LAN computers).
PS : don’t make me install OpenVPN ^^
