Re: ARP Address Conflict Detection and dhcpcd arping

[rudolf <netbsd%eq.cz@localhost>]

Hi Roy,

Roy Marples wrote:
> On 14/10/2019 11:35, rudolf wrote:
> > Looking at the patch you've attached I guess the culprit is probably 
> > that due to the direct connect, the wm0 address is tentative at the 
> > moment of the arping (the link goes up and down several times before 
> > the arping) and thus not being defended?
>
> Well, the culprit is the link going up and down.
>
> dhcpcd ARPing is basically a DaD probe.
> The NetBSD host is also performing DaD each time the link comes up and 
> it correctly spots dhcpcd ARPing for it and marks it's address as 
> duplicated.

OK, I see. Makes sense.

> The only software fix would be to configure dhcpcd to unicast the ARP 
> for the IP address to a specific MAC address that you would need to 
> configure.
> If this is acceptable, I can work on a patch for dhcpcd.
>
> Let me know.

I am perfectly fine with the existing mechanisms in dhcpcd, now that I 
know what is happening and why. Thanks!

r.