ExtremeSwitching (EXOS/Switch Engine)

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 Port=1:45: Illegal STP BPDU format 45

dleboeuf's profile image
dleboeuf posted 05-26-2022 10:52

We recently installed a new stack of 5420Fs running firmware version and I keep seeing these log messages multiple times a day "<Erro:STP.InBPDU.Drop> Slot-1: Port=1:45: Illegal STP BPDU format 45." I can't really seem to find any documentation online regarding this Illegal STP BPDU format error message, which is why I am here. When I check LLDP neighbors on that port, it looks like there is just a laptop on the other end, I am getting a Microsoft MAC address on the port. Should I configure this port as an edge port? Looks like it is set to auto, but is showing up as a point-to-point port which doesn't seem correct, but maybe it is? Not too familiar with STP on EXOS. 

Gabriel_G's profile image

That's an interesting one, I would imagine that there is a packet that is being recognized as STP but it isn't STP in reality. I would generally say to set that port as link-type edge if it is not connected to another networking device. Link-type auto should detect the port as edge, but since the switch thinks that it's getting a BPDU, that may be why it's putting it as P2P. That may stop the log messages, but you may need to perform a PCAP on the client machine at the time of the logs to see if you can identify what packet is triggering that message.

Hope that helps!