Re: IPv6 networking problems in 14.3

> On 17 Sep 2025, at 06:56, Karl Denninger <karl@denninger.net> wrote:
>> 
>> 
>> Oh. So with a new interface, dhcpcd isn’t trying to REBIND, so it’s a different
>> process. I’m not seeing any response to the SOLICIT messages, but I admit that I
>> wasn’t watching the DHCPv6 ports earlier, only the ICMP6, so this may not be
>> new.
>> 
>> This is all for tonight. I’ll try more tomorrow. Thanks all for your time.
>> 
>> 
> That is precisely what it was doing here when my ISP had a hissy-fit due to cached (on their end) association between the ONT/MAC/duid.
> They said it would eventually clear (after their pltime expired -- about 2 weeks!) but obviously that's not really an answer; as soon as they "kicked it" on their end it came up immediately.

Yeah, and I agree that’s possible.  But, this began as soon as I upgraded to
14.3 on August 8.  Interestingly, looking at my dhcpcd.log to confirm dates
and times, I see something related to pltime.
It looks like when dhcpcd starts up, it sets pltime infinity on the local
interface addresses, and then after getting the REPLY6 resets them to
7200 seconds.  Even now, I’m noticing looking more, that while I’m seeing the
“LL of router is unreachable” from dhcpcd every few seconds, every hour
it will multicast a RENEW6, and get back a REPLY6.  At which point it will
add addresses to the internal interfaces, but still the same 3 seconds
later will indicate the routers LL address is unreachable.

I see a few days back in March when the router was unreachable 
intermittently, but back in a minute or so each time.  And a small
flap once in July.  But since Aug 09, always unreachable.  So, it
nearly _has_ to be related to the 14.3 upgrade, although it certainly
may be that 14.3 is different, not wrong, and the ISP is doing
sometime unpleasant.  I’m not sure how to test that.

But, at least I’ve ruled out the vlan interface being the problem,
since I’m in exactly the same state with an ix interface to the
ISP now.

So, on the idea of trying to back-date the whole machine, I have ZFS
snapshots of the whole root from just before the first upgrade,
Aug 7/8.  But in googling around, I didn’t see a clear indication
that I could keep where I am, try swithching to that to run for 
a while, then switch back.  If someone has a guide to doing that,
respond off-list (off freebsd-net at least).  I thought I’d answered
the kernel question, but last night showed that 14.1 kernel doesn’t
always work, to be sure.  If I can run as 14.1 again, for a few days
or weeks, it will confirm at least that it’s my side for sure that’s
changed.

- Chris