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Date:      Sun, 27 Nov 2022 12:55:02 +0100
From:      FreeBSD User <freebsd@walstatt-de.de>
To:        "Andrey V. Elsukov" <bu7cher@yandex.ru>
Cc:        freebsd-ipfw@freebsd.org, freebsd-net@freebsd.org
Subject:   Re: NPTv6: prefix doesn't change in IPFW when prefix changes on dynamic interface
Message-ID:  <20221127125522.0b095dee@thor.intern.walstatt.dynvpn.de>
In-Reply-To: <28091d68-ec5a-8b9d-eb0d-9f8c8728bfa6@yandex.ru>
References:  <20221124162745.7589cf29@thor.intern.walstatt.dynvpn.de> <28091d68-ec5a-8b9d-eb0d-9f8c8728bfa6@yandex.ru>

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Am Fri, 25 Nov 2022 10:40:31 +0300
"Andrey V. Elsukov" <bu7cher@yandex.ru> schrieb:

> 24.11.2022 18:27, FreeBSD User =D0=BF=D0=B8=D1=88=D0=B5=D1=82:
> > Hello,
> >=20
> > running a small routing/firewall applicance based on 13-STABLE and IPFW=
, I face a problem
> > with NPTv6. The external IPv6 is changing dynamically. While ipfw in-ke=
rnel NAT catch up
> > with dynamical changes of the IPv4, NPTv6 doesn't seem so.
> >=20
> > I'm neither an expert in networking nor IPFW.
> >=20
> > After a couple of days tun0 (the exterior PPP interface, uplink connect=
ion managed via
> > mpd5) has a lot of IPV6 addresses, all but one are marked "deprecated".=
 =20
>=20
> > In case nor mpd5 is restarted or the exterior interface is assigned wit=
h several IPv6
> > addresses of which all but one are marked deprecated, pinging the outsi=
de world via IPv6
> > will take the wrong IPv6 - IPFW doesn't seem to catch up with the chang=
es.
> >=20
> > How to fix this? =20
>=20
> Hi,
>=20
> probably the easiest way to solve your problem is periodically running=20
> some script that will find and delete deprecated addresses from an=20
> interface.
>=20
> Then NPTv6 module will use first global prefix on the interface.
>=20

I realized some strange behaviour and I wasn't able to come along with it.

=46rom the net behind the firewall/router after either the router appliance h=
as been rebooted or
ipfw restarted, "ping -6 freebsd.org" works from any host, but not from the=
 router/firewall
itself.
After my ISP has changed both the IPv4 AND IPv6 and tun0, the exterior-poin=
ting PPP interface
has got at least one deprecated IPV6 address (it is also a "temporary IPv6 =
address" created to
hide the MAC of the exterior interface), the router itself is capable of pi=
nging IPv6
addresses in the outside world. But no host within my LAN is.=20
Simply deleting all "deprecated" marked IPv6 addresses from the tun0 interf=
ace doesn't change
anything.

NPTv6 is configured to use tun0, not an IPv6 prefix.

IPv6 routing on the router done via its link-local fe80... address, if this=
 is of interest.

I think I have to investigate the packet flow within IPFW and would like to=
 ask wheter there
is a kind of monitor?

Thanks and kind regards,

O. Hartmann

--=20
O. Hartmann



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