3 x NA from host sent immediately after getting an RA ?

[Marco Moock]

Am Mon, 19 Aug 2024 18:22:55 -0400
schrieb vom513 <vom513 at gmail.com>:

> Something that struck me as curious (could just be ignorance) - is
> that right after getting an RA on the ppp link, my host sends 3 NA’s.
>  These have override set (so is this roughly the equivalent of an
> IPv4 gratuitous ARP ?).

Should not create any problem.

> Here is the pcap if anyone wants to see: https://burn.net/dad.pcap
> 
> Furthermore, the host then complains about a duplicate address on the
> link. (it’s own).

Then it is buggy.
In the capture I see that no source link-layer field exists. I also see
no ethernet header, so the MAC address can't be used as criteria. This
might be related to PPP. I think PPP needs DAD in a special way that
isn't handled properly in the OS/applications you currently run.

> So my first question is - is this behavior documented in an RFC
> anywhere ?

I found something about PPP and DAD:
https://www.rfc-editor.org/rfc/rfc7527