I've ran into a strange problem; at least strange for me.
(all connections are made via wifi, except between the two routers, and router to internet)
Everything was working fine connecting to the router's wifi. A second router was connected via cable to the first one. After connecting to the second router via wifi, neither of them will grant internet access. Devices that have not connected to the second router can still gain internet access through the first router.
I can temporarily fix the problem by changing my hostname and mac address and connecting to the first router with the new identity. However, this fix will only last for the current session. Even though I make the hostname and MAC address changes persistent, I will need to make a new identity next session in order to gain internet access.
The same thing happened with a mobile device. Once it connected with the new router, it can no longer gain net access from either.
It looks to me like the first router learns to block the identities that have connected through the second router. How exactly it comes to that decision, I have no idea.
Has anybody seen something like this before?