Swisscom IPv6 via 6rd not working for a few months

[lucaberta]

Hello everyone,

I had been successfully using 6rd on my Swisscom VDSL2 line for more than a year, running OPNsense on an PCengines APU box with a Zyxel router used a plain modem, with OPNsense taking care of all things IP.

Sometimes around the last few months of 2022, I noticed that IPv6 stopped working after an update of OPNsense, but had no time to troubleshoot the issue.

A few more updates have happened, including 23.1_6 which I am now running, but it still looks like 6rd does not seem to work. Now I am taking some time to try and understand where the issue lies.

A couple of packet captures on the WAN interface igb0 port did not show any incoming traffic from the 6rd border relay, whereby the simple ping6 traffic to www.google.com would be normally visible, encapsulated into 6rd with destination the Swisscom 6rd border gateway.

Capturing traffic on wan_stf also shows the IPv6 traffic, of course before the 6rd encapsulation, with only outgoing ping6 traffic.

Please note that this is IPv6 originating from the OPNsense box via the shell CLI.

A quick ifconfig shows this configuration for the wan_stf interface:

wan_stf: flags=4041<UP,RUNNING,LINK2> metric 0 mtu 1452
   description: WAN (wan)
   inet6 2a02:1205:xxxx:xxxx:: prefixlen 28
   groups: stf
   v4net xx.xxx.xxx.xx/0 -> tv4br 193.5.29.1
   nd6 options=101<PERFORMNUD,NO_DAD>

Can anyone comment on what might be the issue?

I have noticed a few mentions of 6rd in the last few releases, could there be any regression bug that I have hit?

Is there any more detailed way to troubleshoot the issue? I am definitely keen to find what caused the issue, as a few months ago things were working fine on my whole LAN with IPv6 thru 6rd on my OPNsense box.

Many thanks,

Luca

[MikeH]

Hey lucaberta

This is not an error, this is intended behaviour  :)

Swisscom shut down their 6rd service (exept for Wingo, according their FAQ, 6rd is still used there).
Swisscom is now using dual stack. For more infos read this thread (german) at the Swisscom Support Community.

Change your settings and hope for the best.
(Can't help you with the settings, not using Swisscom here.)

Have a great day

Mike

[lucaberta]

Thanks a lot Mike!

I had no clue that 6rd had been switched off on the Swisscom network, and of course no mention of this was made to the users.

Swisscom makes it very difficult to NOT use their official equipment, and luckily the Swisscom community forum are quite helpful, though not speaking German is sometimes an issue...

It's time to reconfigure IPv6 and make things work again!

Many thanks,

Luca

[MikeH]

Hi Luca

Well, Swisscom is not known to be 3rd-party-hardware-friendly, that's probably why they dont't have any official info about any settings for your own router (e.g. DHCP Option 60, VLAN on fiber). Not even the VLAN settings for the GSM booster for your own managed switch are available. They expect you to buy everything from their store, else they won't give you any support. Kind of a vendor lock-in or golden cage... The support community is the only hope. Maybe it's time to change your internet provider.

But any other ISP has it's own quirks, PPPoE (ugly on BSD for faster lines), too expensive, no documentation on IPv6 and even support is clueless (after try and error I got it working with 6to4 tunnel)...

There is no such thing as perfect internet...

Let us know if and how you got it working.

Greetings Mike

[lucaberta]

Well, to be fair to Swisscom, they do have minimal documentation on the settings for 3rd party equipment to connect to their network on this page:

https://www.swisscom.ch/en/residential/help/device/internet-router/external-router.html

What they don't clearly say is that navigation to this page in order for the network to "learn" about your router becomes mandatory, otherwise you will not access the Internet:

http://swisscom.ch/start

In general I am quite happy with their service... though I still need to tinker with the IGMP configuration in order to use the Swisscom TV box, which is no big deal as we almost never watch live TV... and for that we use the BlueTV app, if need be.

As far as other ISPs are concerned, I live in a rural area and get VDSL2 from Swisscom via FTTC, and some 15 meters of  copper to my home, giving me some 650M down and 150M up, so I cannot complain!

What other ISPs have you tested here in Switzerland?

Greetings from the "La Côte" area, halfway between Lausanne and Geneva, at the foothills of the Jura mountains!

Bye, Luca

[MikeH]

Well, to be fair to Swisscom, they do have minimal documentation on the settings for 3rd party equipment to connect to their network on this page:

https://www.swisscom.ch/en/residential/help/device/internet-router/external-router.html

Oh, this is a new one for me. I'm actually surprised, in a positive way...
Still not mentioning anything about IPv6 but better than nothing.

In general I am quite happy with their service... though I still need to tinker with the IGMP configuration in order to use the Swisscom TV box, which is no big deal as we almost never watch live TV... and for that we use the BlueTV app, if need be.

Yeah, the TV is without any doubt one of the best. But my TV usage is almost zero, so no reason to go Swisscom...

As far as other ISPs are concerned, I live in a rural area and get VDSL2 from Swisscom via FTTC, and some 15 meters of  copper to my home, giving me some 650M down and 150M up, so I cannot complain!

You got a better line than me, I'm on 480/120 brutto, or around 430/112 netto. mCAN is only a few meters away, but the line is a little longer (goes around the house).

What other ISPs have you tested here in Switzerland?

• I had Swisscom until a few years ago, when you could still switch the router to bridge mode (centro piccolo time)
• I'm with Init7 now, all fine (same IPv4 address since ever, fixed IPV6 /48 range, support is nice) but it's a little bit on on the more expensive side for my 430/110 line (could go cheaper with a different provider)
• Green (at my parents): Internet and Voip is very good, everything with IPv6 is real shit. They don't have any Info about IPv6 on their website, support could not answer my question how it is assigned (2 Tickets and still no answer). A blog entry about IPv6 ("all our connections are IPv6 ready") was deleted after I mentioned it in my ticket. After testing I found out 6to4 tunnel is used. Either I had bad luck or IPv6 is Neuland for green. And they just rised prices, about 10.- per month (only for new contracts, we will see how long it takes until they change our contract
• Thinking about changing to openfactory/sixsixsix, but their checker is borked... Had a few questions and support was very nice and competent

Unfortunately most ISP on BBCS (Swisscom Line) are using PPPoE, this is really a bummer on *sense/BSD...

Greetings from the "La Côte" area, halfway between Lausanne and Geneva, at the foothills of the Jura mountains!

Greetings from next to Thun (lake, mountains, nice old town :P )

Mike