Clients in separate subnets unable to communicate


I have 2 machines advertising the following routes:

  • Machine A:
  • Machine B:

All clients behind each subnet are able to communicate via the subnet routers just fine, until today when Client A (, Linux 3.2.0 ARMv7) and Client B (, Debian 10) stopped communicating with each other. As far as I’m aware there are no firewalls present on each client (no firewalld, ufw is inactive).