I recently bought some Grandstream GWN7672L access points to set up a mesh Wi-Fi network (wireless backhaul), and I'm noticing problems with mDNS and ICMP6 traffic. Specifically, it seems like the dst MAC address for IPv6 multicast frames gets rewritten from something like 33:33:00:00:00:fb (for mDNS) to 33:33:80:00:ff:ff.
Devices are just ignoring/dropping the traffic because that's not a multicast address that they recognize or are listening to.
Turning off the mesh Wi-Fi feature fixes the issue immediately (no corruption).
Anybody else having this problem?
Source: r/GrandstreamNetworks · by /u/rogerhub