Bug 221754

Summary:	arp: packet with invalid ethernet address length 0 received
Product:	Base System	Reporter:	Pavel Zhe <pzhel>
Component:	kern	Assignee:	freebsd-net (Nobody) <net>
Status:	New ---
Severity:	Affects Only Me	CC:	inoue.takashi
Priority:	---
Version:	11.1-RELEASE
Hardware:	amd64
OS:	Any

Description Pavel Zhe 2017-08-24 06:36:35 UTC

We have two Virtual FreeBSD machines on Hyper-V 2008R2 server. 
VM#1 - FreeBSD 10.3-RELEASE-p18 amd64
VM#2 - FreeBSD 11.1-RELEASE amd64

Both VM's connected to the same LAN 192.168.0.0/17

On VM#2 /var/log/messages permanently registering an error

arp: packet with invalid ethernet address length 0 received on hn0

tcpdump on hn0 show this

17:48:17.035879 ARP, Ethernet (len 0), Unknown Protocol (0xf000) (len 1), length 50

Quick Google search show that such packets can be generated by D-Link DES/DGS Metro series switches. We have a number of D-Link switches in our LAN, but we never see this error on FreeBSD 8.x/9.x/10.x before

Can it be fixed?
Or,how we can supress this error messages on 11.1, because replacing D-Link switches is not a solution.

Comment 1 Pavel Zhe 2017-08-24 12:36:14 UTC

The source of problem was D-Link DES1100-16 with enabled 'loopback detection' on uplink port (switch was reseted to factory settings early).  After that as 'loopback detection' was turned off on this (uplink) port, error disappeared from log. 

Anyway, a method to handling this error is required.

Comment 2 Taka 2018-10-10 18:53:20 UTC

I'm also getting this message a lot.
Is there any progress?