It seems like packets are discarded when they contain "LLDP-MED Capabilities" Update - I disabled LLDP-MED in LLDPD configuration and see: Same applies on other devices on the network.

@whereisaaron Could you also supply a tcdump of the ER7412? Just because I am interested. whereisaaron wrote @Ethan-TP thanks for the info! I fully understand that LLDP packets are not propagated,...

@Ethan-TP Please find attached the tcpdump. It is collected at the OPNsense port re1 (FreeBSD router), which is directly connected to the TP-link 2.5 Gbit Port 2.

@Ethan-TP This does not explain, why the packets are ignored by the switch...

@whereisaaron I have several devices transmitting lldp Messages and all of them are received fine. Also the structure and content is the Same Like the Message from OPNsense. I sniffed it with tcpdump...

@whereisaaron I have also a port connected to a EAP682 which is also working with 2.5Gbit. It is also working. The not working port is also connected to an OPNsense Router. Btw.. I have LLDPD running...