[Starlink] dhcpv6-pd details

[Nick Buraglio]

Inline

On Mon, May 17, 2021 at 2:15 PM Dave Taht <dave.taht at gmail.com> wrote:
>
> On Mon, May 17, 2021 at 12:04 PM Nick Buraglio <nick at buraglio.com> wrote:
> >
> > As discussed privately with Dave, I have removed the starlink provided
> > router and replaced it with a Mikrotik RB2011 to allow for more
>
> Running routerOS? Latest beta's of that have cake in 'em.

I have the latest on a device in my home lab, but it's definitely not
ready for prime time.
Here are some packet captures directly from the Mikrotik using the
"sniffer" command. It's not terribly useful, but here it is:

reading from file dhcpv6, link-type EN10MB (Ethernet)
14:16:54.570633 IP6 fe80::4e5e:cff:fe1a:7f3d.546 > ff02::1:2.547: dhcp6 release
14:17:03.087352 IP6 fe80::4e5e:cff:fe1a:7f3d.546 > ff02::1:2.547: dhcp6 solicit
14:17:03.142612 IP6 fe80::1.547 > fe80::4e5e:cff:fe1a:7f3d.546: dhcp6 advertise
14:17:04.035913 IP6 fe80::4e5e:cff:fe1a:7f3d.546 > ff02::1:2.547: dhcp6 request
14:17:04.075914 IP6 fe80::1.547 > fe80::4e5e:cff:fe1a:7f3d.546: dhcp6 reply

>
> > granular control, and to better tie into my existing network.
>
> Starlink provides a router, also? I'm so confused. I thought the dishy
> was all there was. Care to tear it apart and describe what's in it?

As far as the "router" is concerned, it's very much a consumer grade
device that is managed via the mobile app. I hated it, so I took it
out. It's still up in the attic. near the cable conduit, if I recall.
>
> > This has
> > allowed me to make a dhcpv6-pd request that is reasonably stable (so
> > far it has changed once in the last 2 months). The lease time is
> > incredibly short, which is a little strange but as long as the DHCPv6
> > server is the same and remains unchanged, it should just hand out the
> > same prefix upon request.
>
> That was a terrible habit that comcast had got into in the early days
> that forced
> openwrt to flush and reload the firewall every minute, or less.
>
> I'd pioneered a stateless firewall in cerowrt that never ever ever
> needed to reload the
> rules, using a pattern match for each specifically renamed ethernet interface.
>
> Regrettably that was not accepted into openwrt, because "nftables" was
> just around the corner.
> It scaled beautifully to tons of interfaces going up and down so long
> as they were named appropriately,
> at far less cpu overhead for complicated rules than the standard
> openwrt firewall.
>
> https://www.bufferbloat.net/projects/cerowrt/wiki/CeroWall/?version=9
>
> Anyway, I don't remember all that we did to suppress the flood of
> useless static changes
> to everything ipv6, but I hope that whatever we ended up doing still
> works in this case.
>
> > I also built a very crude measurement display that just uses curl get
> > and dig via smokeping to display reasonable RTT. It's detailed in the
> > reddit post here:
> > https://www.reddit.com/r/Starlink/comments/mykxjv/functional_ipv6_and_some_crude_starlink_latency/
> > and can be viewed directly here:
> > https://starmon.qosbox.com/
>
> THX! We really need to collect the "good" information and publish it
> somewhere, the reddit noise level is too high.
>
> One piece of mis-information I think was the news you can "route"
> packets over ipv4 with a box in front of it and
> a default gw of 192.168.100.1 Not clear from that news whether or not
> NAT was required on the next hop or not... ?

The 192.168.100.1 address is the default address of the dish, all of
the statistical information resides on the dish itself. With a simple
static route it is pretty simple to remove the home wifi gateway
mentioned above and just look at the statistics on the disk itself -
it's literally just a web page and an API. The 192.168.100.1 is
similar to the cable modem bridges that display their channel sync
statistics, it's a commonly used address on CPE. As far as NAT, it's
all CGN, so there is no public IPv4 addressing (hence my strong desire
to make IPv6 work ASAP). All IP space seems to be delegated from
Google in one way or another, v4 and v6 are both via GoogleWifi
(AS36492). First hop transit is Google (AS15169), so it looks a lot
like the google fiber backbone.

>
> (that's from another reddit post I mis-remember)
>
> >
> > Making dhcpv6-pd work is pretty standard:
> >
> > /ipv6 dhcp-client
> >
> > add add-default-route=yes interface=ether2 pool-name=starlink-ipv6
> > prefix-hint=::/56 request=prefix
> >
> > On each interface you want to have IPv6 on:
> >
> > /ipv6 address
> >
> > add address=::1 from-pool=starlink-ipv6 interface=bridge.8
> >
> > add address=::1 from-pool=starlink-ipv6 interface=bridge.6
>
> THANKS SO MUCH. I am thinking at the moment that openwrt's dhcp-pd
> implementation is currently
> broken (it's not working on admittedly a comcast modem I just got that
> I'd not used before), but
> as soon as I get a chance I'll try configuring odhcpd6 to do something
> like this. If I can remember how.
>
>
> > _______________________________________________
> > Starlink mailing list
> > Starlink at lists.bufferbloat.net
> > https://lists.bufferbloat.net/listinfo/starlink
>
>
>
> --
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>
> Dave Täht CTO, TekLibre, LLC