80% package loss on tunnel

[steinarb]

I have created an HE IPv6 tunnel from my rPi router, running raspbian/raspberry pi os 11.6 "bullseye".

However, the only thing that works over the tunnel is ping and traceroute, and they both see an 80% packet loss.

Everything else I've tried just times out.

Any ideas to how to further investigate this, and what the cause might be, are most welcome.

If someone can suggest a fix/workaround I would be even happier.

I suspect, but cannot confirm or deny, that the problem is in the routing of protocol 41 packets over IPv4 between my ISP and he.net

What I see, is:

• 80% packet loss in the tunnel, going from the rPi to a VPS in the cloud (mtr, traceroute and ping)
• 80% packet loss from a VPS in the cloud and to the rPi (mtr, traceroute and ping)
• 0% loss on an IPv4 mtr traceroute from the rPi to the HE tunnel endpoint
• 0% loss on an IPv4 tracroute from the HE tunnel endpoint and to the rPi (traceroute done by HE)
• 0% loss on an IPv6 tracroute from my VPS in the cloud to the HE tunnel endpoint

The tracroute results can be found further down in the post.

On the rPi side, the tunnel is created with the following /etc/network/interfaces entry, supplied by the [tunnel config pages](https://www.tunnelbroker.net/) (selected "Debian/Ubuntu" from the dropdown):

Code Select Expand

auto he-ipv6
iface he-ipv6 inet6 v4tunnel
        address 2001:470:27:933::2
        netmask 64
        endpoint 216.66.80.90
        local 84.210.69.52
        ttl 255
        gateway 2001:470:27:933::1

The MTU of the tunnel is set to the default 1480, which is also the max value allowed.

Here comes the traceroute results:

From my rPi router to my cloud VPS:

Code Select Expand

                            My traceroute  [v0.94]
ocon (2001:470:27:933::2) -> schwantz.bang.priv.no     2023-02-27T23:28:30+0100
Keys:  Help   Display mode   Restart statistics   Order of fields   quit
                                       Packets               Pings
 Host                                Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. tunnel820211.tunnel.tserv24.sto1 86.6%   113  110.7  58.3  33.8 173.2  41.6
 2. e0-22.core2.sto1.he.net          86.6%   113   32.6  34.0  31.4  51.4   4.9
 3. as24940-100g-ix1.sthix.net       88.4%   113   32.2  53.3  32.1 142.6  38.5
 4. core32.hel1.hetzner.com          89.3%   113   54.9  66.6  36.8 176.3  46.2
 5. 2a01:4f9:0:c001::a072            88.4%   113   80.4  67.3  36.6 160.4  45.3
 6. (waiting for reply)
 7. 20953.your-cloud.host            88.4%   113   38.1  38.0  36.6  44.5   2.0
 8. schwantz.bang.priv.no            88.3%   112   40.4  64.5  36.4 173.5  49.4

Going the other way, from my VPS to my rPi router

Code Select Expand

                             My traceroute  [v0.94]
schwantz (2a01:4f9:c011:82fd::1) -> ocon.bang.priv.no  2023-02-27T22:30:43+0000
Keys:  Help   Display mode   Restart statistics   Order of fields   quit
                                       Packets               Pings
 Host                                Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. fe80::                            0.0%    53    1.6   1.5   1.3   2.0   0.1
 2. 20953.your-cloud.host             0.0%    53    0.3   0.3   0.3   0.6   0.1
 3. 2a01:4f9:0:c001::2b01             0.0%    53    6.1  12.9   0.6 138.2  28.1
 4. 2a01:4f9:0:c001::a0f9             0.0%    53    0.8   6.5   0.8  51.9  13.0
 5. 2a01:4f9:0:c001::a071             0.0%    53    0.8   3.8   0.3  27.5   5.7
 6. juniper4.dc1.hel1.hetzner.com     0.0%    53    0.6   2.9   0.4  47.3   8.8
 7. (waiting for reply)
 8. (waiting for reply)
 9. as6939-20g-sk1.sthix.net          0.0%    52    6.9   8.7   6.4  25.3   5.2
10. tserv1.sto1.he.net                7.7%    52   12.9  13.2   7.8 105.8  18.9
11. tunnel820211-pt.tunnel.tserv24.s 80.4%    52   36.7  48.2  36.4  92.3  20.7

Here are the results of running "mtr -4 tserv1.sto1.he.net" from the rPi:

Code Select Expand

                             My traceroute  [v0.94]
ocon (84.210.69.52) -> tserv1.sto1.he.net              2023-02-28T21:06:45+0100
Keys:  Help   Display mode   Restart statistics   Order of fields   quit
                                       Packets               Pings
 Host                                Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. 10.232.0.1                        0.0%    45   47.1  11.3   6.8  47.1   8.4
 2. cm-84.208.41.56.get.no            0.0%    45    6.8   9.9   4.5  41.9   7.2
 3. peer-as41164.san-peer2.osl.no.ip  0.0%    45    7.5  10.1   7.5  34.4   5.3
 4. 109.163.76.160                    0.0%    44    8.6  11.8   6.9  43.6   8.3
 5. oso-b1-link.ip.twelve99.net       0.0%    44    8.3   9.2   7.9  11.4   0.8
 6. hbg-bb3-link.ip.twelve99.net     51.2%    44   21.6  22.0  19.6  41.1   4.5
 7. adm-bb1-link.ip.twelve99.net      0.0%    44   26.8  27.7  26.1  44.5   2.8
 8. adm-b1-link.ip.twelve99.net       0.0%    44   27.1  33.2  26.5 100.5  16.9
 9. hurricane-svc080870-ic370722.ip. 81.4%    44   44.3  52.2  27.6 101.2  28.5
10. hurricane-svc083420-ic373456.ip. 97.7%    44   42.7  42.7  42.7  42.7   0.0
11. port-channel5.core2.sto1.he.net   0.0%    44   53.2  34.4  30.4  61.6   7.4
12. tserv1.sto1.he.net                0.0%    44   64.7  36.5  30.4 109.9  16.3

IPv6 mtr from my VPS in the cloud and to tserv1.sto1.he.net show now obstructions whatsoever:

Code Select Expand

                             My traceroute  [v0.94]
schwantz (2a01:4f9:c011:82fd::1) -> tserv1.sto1.he.net 2023-03-03T16:44:21+0000
Keys:  Help   Display mode   Restart statistics   Order of fields   quit
                                       Packets               Pings
 Host                                Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. fe80::                            0.0%    42    1.3   1.6   1.3   2.3   0.2
 2. 20953.your-cloud.host             0.0%    42    0.3   0.3   0.3   0.6   0.1
 3. 2a01:4f9:0:c001::2b01             0.0%    42   23.3  29.7   7.0 172.8  33.4
 4. 2a01:4f9:0:c001::a0f9             0.0%    42    0.8   4.7   0.8  43.3   9.6
 5. 2a01:4f9:0:c001::a071             0.0%    41    5.5   4.3   0.4  40.2   8.3
 6. juniper5.dc1.hel1.hetzner.com     0.0%    41    0.4   1.1   0.4  19.8   3.0
 7. (waiting for reply)
 8. (waiting for reply)
 9. as6939-20g-sk1.sthix.net          0.0%    41    7.1   7.8   6.6  30.7   4.4
10. tserv1.sto1.he.net                0.0%    41    6.0  13.3   5.8  98.2  19.9