I am troubleshooting a LAN and the problem is to make sure each host can reach each other at layer 3. Each host is configured to the same subnet, but some hosts cannot reach other at layer 3 (e.g. ping
says host other is down). Before checking for layer 3 problems, we want to establish that Ethernet (up to layer 2) is working properly and that each of the hosts can discover each other. We have the set of each host MAC address to connect.
Relying on only layers 1-2, what are the suggested methods to make sure layer 2 works?
Guesses
- tools which make the host interface run in promiscuous mode
- some use of
FF:FF:FF:FF:FF:FF
broadcast - There was a related layer 2 question which hinted at some possible topology discover protocols but it was closed.