Today I ran into a really weird problem. We are all PPPoE and use the Mikrotik router to feed a VLAN switch that connects to our tower sites. The VLAN switches isolate all our PPPoE users. We also assign a 10.0.0.0/16 IP to this interface for modem management. Been this way for years and has worked fine. No user can directly talk to another without going through the Mikrotik router.
Today all of a sudden I no longer could ping 10.0.0.x IP’s or connect to them. Try to ping them and they do not even show up in ARP cache. For a while a few work then after a router reboot none work. Replaced VLAN switch. Still no go. Loaded an old backup that was known working in router. Still no work. Replaced entire router with backup. Still no go. Unplugged connections from VLAN switch one by one trying it each time. After unplugging an AP-10D with about 20 users on it the problem went away. After rebooting the AP-10d and plugging it back in problem stayed away.
Any idea what was/is going on?
Matt