topic Re: Plusnet Gateway dropping IPv6 tunnel data in Everything else

Plusnet Gateway dropping IPv6 tunnel data

RPMozley — Wed, 22 Jan 2025 19:04:22 GMT

The Gateway with IP 195.166.130.254 appears to be dropping or blocking 6in4 tunnel traffic from Hurricane Electric. This results in timeouts for IPv6 connections.

Is anyone else seeing this behaviour who are also with HE?

Re: Plusnet Gateway dropping IPv6 tunnel data

outcast — Wed, 22 Jan 2025 20:00:35 GMT

@RPMozley is your H.E. tunnel endpoint in London the server "tserv1.lon2" ?

- that device is currently showing a warning - "New tunnels temporarily disabled due to high usage"

The other H.E. London endpoints "tserv5.lon1" and "tserv17.lon1" are not reporting any issues.

I would have tried to help you by attempting to reproduce your problem on my setup, having used an H.E. tunnel for about eleven years, but I now have native IPv6, and my H.E. tunnel config has been cleared out of my router.

If you are on "tserv1.lon2", then just go into your Tunnelbroker account, change the endpoint to one of the others, then update the tunnel IP address in your router to match. (that's what I had to do when my "tserv5.lon1" endpoint went down for a month).

Re: Plusnet Gateway dropping IPv6 tunnel data

RPMozley — Wed, 22 Jan 2025 22:14:59 GMT

I’m aware of that server issue but my tunnel is to “5.1” and not “1.2”.
The tunnel works perfectly fine on my current gateway server “195.166.130.251”.
There seems to be something different with the 195.166.130.254 gateway.

Thanks for your input though @outcast
(Typing on mobile)

Re: Plusnet Gateway dropping IPv6 tunnel data

RPMozley — Thu, 30 Jan 2025 22:40:57 GMT

Gateway "195.166.130.255" is also showing the same odd behaviour as the one I mentioned earlier.

Now I have to try and get on a different gateway, which isn't always easy, to get IPv6 traffic flowing again.

Re: Plusnet Gateway dropping IPv6 tunnel data

outcast — Thu, 30 Jan 2025 23:08:07 GMT

The only person on here that I can think could look at this for you is @dave ?

Re: Plusnet Gateway dropping IPv6 tunnel data

outcast — Thu, 30 Jan 2025 23:27:01 GMT

@RPMozley what part of England are you in ?

I'm not far from London, and both my Plusnet gateway and Hurricane Electric tunnel gateway were in Telehouse London, so likely located in the same building ? - and if anything I had better internet connectivity over the HE IPv6 tunnel than I got on native Plusnet IPv4 routes, certainly less hops, near identical speed, and just a 0.3ms latency penalty.

I'm wondering if you were in a different part of the country, whether your Hurricane Electric endpoint might be in Manchester, Leeds, Slough, Edinburgh, and 'might' be a transit issue that could be region specific to your nearest Plusnet gateway ?

Hurricane Electric's UK locations are listed on page 2 of this map - http://he.net/HurricaneElectricNetworkMap.pdf

Re: Plusnet Gateway dropping IPv6 tunnel data

RPMozley — Fri, 31 Jan 2025 20:56:29 GMT

Certainly Dave would probably be able to find out, if he's still around and not moved on to other areas or companies.

I don't think in this case, location is a factor because I believe all PN gateways are located in London. But for info we're located in Gloucestershire.

I think it was still possible to ping an IPv6 address directly but times out with a domain name. I'll have to do some more testing once we get kicked onto a "problem" gateway.

Re: Plusnet Gateway dropping IPv6 tunnel data

dave — Mon, 03 Feb 2025 09:53:01 GMT

@RPMozley I'm still around. We have made some changes on the network over the last few months. Does it still work on any of the gateway IPs? There are currently 3 different ones in service so would be good to know if it works on any of them?

Re: Plusnet Gateway dropping IPv6 tunnel data

outcast — Mon, 03 Feb 2025 10:11:49 GMT

@dave wrote:

... There are currently 3 different ones in service so would be good to know if it works on any of them?

@dave from @RPMozley 's replies #1 , #3 and #4 , if I read it correctly,

it appears that gateway 195.166.130.251 is working

but 195.166.130.254 and 195.166.130.255 are not.

Re: Plusnet Gateway dropping IPv6 tunnel data

dave — Tue, 04 Feb 2025 12:31:15 GMT

I've just set up n account with he.net's tunnel broker and tested on 2 of the 3 active devices: 195.166.130.254 and 195.166.130.251.

I'm using a Mac (internal IP 192.168.1.116) and did the following to set it up:

ifconfig gif0 create
ifconfig gif0 tunnel 192.168.1.116 209.51.161.14
ifconfig gif0 inet6 2001:470:<snip>::2 2001:470:<snip>::1 prefixlen 128
route -n add -inet6 default 2001:470:<snip>::1

ifconfig shows the following:

gif0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1280
tunnel inet 192.168.1.116 --> 209.51.161.14
inet6 fe80::60b1:5232:61c4:17ee%gif0 prefixlen 64 scopeid 0x2
inet6 2001:470:<snip>::2 --> 2001:470:<snip>::1 prefixlen 128
nd6 options=201<PERFORMNUD,DAD>

ping6 ipv6.google.com works fine on both
PING6(56=40+8+8 bytes) 2001:470:<snip>::2 --> 2a00:1450:4009:815::200e
16 bytes from 2a00:1450:4009:815::200e, icmp_seq=0 hlim=120 time=147.552 ms
16 bytes from 2a00:1450:4009:815::200e, icmp_seq=1 hlim=120 time=146.848 ms
16 bytes from 2a00:1450:4009:815::200e, icmp_seq=2 hlim=120 time=242.870 ms
16 bytes from 2a00:1450:4009:815::200e, icmp_seq=3 hlim=120 time=281.020 ms
16 bytes from 2a00:1450:4009:815::200e, icmp_seq=4 hlim=120 time=320.368 ms
16 bytes from 2a00:1450:4009:815::200e, icmp_seq=5 hlim=120 time=145.196 ms
^C
--- ipv6.l.google.com ping6 statistics ---
6 packets transmitted, 6 packets received, 0.0% packet loss

The IPv4 tunnel end point I have is 209.51.161.14, which are you using? And do you see dropped packets on the ping?

Re: Plusnet Gateway dropping IPv6 tunnel data

outcast — Tue, 04 Feb 2025 13:12:38 GMT

@dave wrote:

The IPv4 tunnel end point I have is 209.51.161.14, which are you using? And do you see dropped packets on the ping?

@dave -

@RPMozley isn't here to answer, but indicates in reply #3 that the H.E. endpoint being used is "tserv5.lon1"

I *think* that "tserv5.lon1.ipv6.he.net" is 216.66.80.26

Re: Plusnet Gateway dropping IPv6 tunnel data

dave — Tue, 04 Feb 2025 13:50:51 GMT

Our broadband network has a different design depending on whether you have a static IP (and a couple of other things) or a dynamic IP address.

For static IPs there are 4 potential gateway IP addresses:

195.166.130.250 & 251 which are devices in Colindale (PCN-BNG03 & PCN-BNG04)

195.166.130.254 & 255 which are devices in Southbank (PSB-BNG03 & PSB-BNG04)

PCN-BNG03 (195.166.130.250) is currently out of service having some maintenance work done on it, it should be back next week if the final tests all pass so we'll ignore that one for now but if we don't work out what's wrong will be interesting to see if that works or not.

There shouldn't be any difference in the design/config on the other 3 so it's odd that it's not working on the 2 Southbank devices. I've just had a scan of 216.66.80.26 to see if I can see any traffic and I can see protocol 41 traffic flows in both directions at both sites. The other main IP I'm seeing is 216.66.88.98 and that also seems to have protocol 41traffic in both directions at both sites. I don't see much else other than some limited volumetrics (traffic is definitely measured in high gigabytes per day not megabytes).

Re: Plusnet Gateway dropping IPv6 tunnel data

outcast — Tue, 04 Feb 2025 14:06:28 GMT

@dave wrote:

I've just had a scan of 216.66.80.26 to see if I can see any traffic and I can see protocol 41 traffic flows in both directions at both sites. The other main IP I'm seeing is 216.66.88.98 and that also seems to have protocol 41traffic in both directions at both sites. I don't see much else ...

@dave

At the Hurricane Electric end there should be three UK endpoints -

"tserv1.lon2"
"tserv5.lon1"
"tserv17.lon1"

Note that "tserv1.lon2" (Tunnel Server Status) is currently reporting "New tunnels temporarily disabled due to high usage"

Re: Plusnet Gateway dropping IPv6 tunnel data

Townman — Tue, 04 Feb 2025 15:28:27 GMT

@dave wrote:

195.166.130.254 & 255 which are devices in Southbank (PSB-BNG03 & PSB-BNG04)

There shouldn't be any difference in the design/config on the other 3 so it's odd that it's not working on the 2 Southbank devices.

@dave

Does that point to the possibility that the issue is caused by some other kit in Southbank other than the readily identifiable gateways. "Out here" we can only identify the gateway touch point, not what other infrastructure might be involved. Could this issue be caused by Southbank peering or "exit" kit / routes?

Possibly a barking idea, but given that the bits which are identifiable are identical, then the issue might well be somewhere else.

Re: Plusnet Gateway dropping IPv6 tunnel data

dave — Tue, 04 Feb 2025 15:42:34 GMT

It's not impossible, but I'd expect to be able to replicate or not see any traffic at Southbank at all. As such need to get a bit of confirmation on @RPMozley's setup.

Re: Plusnet Gateway dropping IPv6 tunnel data

outcast — Tue, 04 Feb 2025 15:50:26 GMT

@dave wrote:

... As such need to get a bit of confirmation on @RPMozley's setup.

@dave can you spell out exactly what you need @RPMozley to tell you, that hasn't already been stated in this thread ?

I used to run an H.E. IPv6 tunnel over Plusnet static IPv4 for about 13 years, and if I was trying to answer you, I wouldn't know what 'confirmation of setup' you are trying to find out ?

Re: Plusnet Gateway dropping IPv6 tunnel data

dave — Tue, 04 Feb 2025 16:01:14 GMT

Good point.

On a Mac/Linux the output of ifconfig showing the relevant tunnel interface (IPv6 address can be redacted)

ifconfig

I think ipconfig /all is the equivalent on Windows (again IPv6 address can be redacted) and only need the tunnel interface.

I'd check to see if they are the same on both a working gateway and none-working one.

Also would be useful get the result of the following on working and none-working gateways:

ping6 ipv6.google.com

traceroute6 ipv6.google.com

Re: Plusnet Gateway dropping IPv6 tunnel data

outcast — Tue, 04 Feb 2025 16:05:04 GMT

Thanks @dave , I guess we'll have to wait for @RPMozley to reappear.

Re: Plusnet Gateway dropping IPv6 tunnel data

RPMozley — Tue, 04 Feb 2025 17:13:46 GMT

Hi all, I’m here now, been a bit preoccupied with other things (mostly concerning my older brother’s cancer op) and I’ve not had a PPP drop that put us on a “problem” gateway.

I did some short testing earlier and I saw some strange results. Currently I’m setup with a Ubuntu based Linux machine connected with ethernet, acting as IPv6 server (along with DHCP and DNS proxy services).
Connectivity was a little off with some IPv6 locations accessible while others just timing out. I tried to find any correlation with the problem sites but it’s not anything clear (not IP address). One possibility is the TLD “.io” (DNS is being provided by NextDNS which uses .io). It’s not entirely clear though as there could be cached responses in play. Ping tests were carried out using “mtr” and were working but slow output possibly due to reverse dns lookups (only Google domain tested).
Testing done while connected to GW .255 and tunnel server 216.66.80.26
Once back on GW .251 connectivity is back to normal.

I think some further longer testing sessions are required to find the diagnosis of the problem.

Re: Plusnet Gateway dropping IPv6 tunnel data

RPMozley — Sat, 08 Feb 2025 20:22:01 GMT

Managed to get in one longer time period testing session during the week (at late night).
TLD turned out to be just a red herring. I first started on test-ipv6.com with a working gateway, all ok. Switched to an “odd” gateway and immediately reloaded test-ipv6, some timeouts seen on two of the tests. Then tried ping -6 -c 10 google.com no problems.
Back to test-ipv6.com even more timeouts on the tests! Another reload and IPv6 connectivity completely broken.
Tested ping google.com again, still no issues.

Completed testing and have to go through the lottery of dropping PPP in the hope of getting back on the only working gateway. Back on gateway .251 and IPv6 is perfectly fine.

Results!
ICMPv6 traffic - unaffected.
All other traffic - timeouts with zero responses.

Possible fixes? (just educated guesswork)
MTU problem? ICMPv6 packets are much smaller than data packets.