Does FreeBSD do proactive ARP refresh?

[sthaug at nethelp.no]

> > I have a reproducible problem on 11.1-STABLE where, during a longterm
> > iperf3 session, some packets are lost every time ARP is refreshed (every
> > net.link.ether.inet.max_age seconds). Checking with tcpdump, I can
> > indeed see that the packet loss is happening as the hosts are doing
> > ARP request/reply.
> I'll take a look. Indeed, the intended behaviour is to proactively refresh the record.
> Is the situation the same with forwarding and locally-originated traffic?
> With local TCP socket inpcb route caching might come into play. 

My testing is with locally-originated UDP traffic (iperf3 -u). Haven't
tested what happens if the box is forwarding the traffic - however, I
believe TCP socket inpcb route caching should not be relevant for the
UDP traffic? (But there is also a TCP transaction between the iperf3
sender and the iperf3 receiver at the *start* of the iperf3 session.)

In any case, I will also test what happens if the box is forwarding
the traffic.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no