Fedora 34 Ipv6 not working

I am in fedora 34 and for some reason my Ipv6 keeps cutting in and out. Sometimes it works and sometimes it doesn’t. I am not a networking guy, so I would appreciate all guidance before I continue. The only thing I noticed that might be it is /etc/resolv.conf doesn’t have an ipv6 DNS, so maybe it is systemd-resolved?

[andythurman@rockhopper ~]$ cat /etc/resolv.conf 
# This is /run/systemd/resolve/stub-resolv.conf managed by man:systemd-resolved(8).
# Do not edit.
#
# This file might be symlinked as /etc/resolv.conf. If you're looking at
# /etc/resolv.conf and seeing this text, you have followed the symlink.
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs should typically not access this file directly, but only
# through the symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a
# different way, replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.

nameserver 127.0.0.53
options edns0 trust-ad
search .

It is making certain things like Geary, git, and Lutris super unpredictable, so I would appreciate any solution. For now, I’m probably just going to swap back to F33 until I can figure something out.

resolvectl flush-caches seems to have fixed it for now, but I would not be surprised if it comes back. Will keep you all updated and still appreciate any support.

2 Likes

And on a reboot it is broken again. Hmmmmmmm.

Internet: receiver good/send bad - #5 by vgaetera

1 Like

Here is the full output when it happens again:

NetworkManager...
STATE      CONNECTIVITY  WIFI-HW  WIFI     WWAN-HW  WWAN    
connected  full          enabled  enabled  enabled  enabled 
NAME    UUID                                  TYPE      DEVICE 
enp3s0  2df4c834-7005-3f61-ad19-ddc7a2668f87  ethernet  enp3s0 
Resolver...
Global:
Link 2 (enp3s0): 192.168.1.254 2600:1700:e20:bfb0::1
Global:
Link 2 (enp3s0): attlocal.net
fedoraproject.org: 140.211.169.196             -- link: enp3s0
                   67.219.144.68               -- link: enp3s0
                   38.145.60.21                -- link: enp3s0
                   152.19.134.142              -- link: enp3s0
                   209.132.190.2               -- link: enp3s0
                   8.43.85.67                  -- link: enp3s0
                   8.43.85.73                  -- link: enp3s0
                   140.211.169.206             -- link: enp3s0
                   152.19.134.198              -- link: enp3s0
                   38.145.60.20                -- link: enp3s0
                   2620:52:3:1:dead:beef:cafe:fed6 -- link: enp3s0
                   2605:bc80:3010:600:dead:beef:cafe:feda -- link: enp3s0
                   2610:28:3090:3001:dead:beef:cafe:fed3 -- link: enp3s0
                   2620:52:3:1:dead:beef:cafe:fed7 -- link: enp3s0
                   2605:bc80:3010:600:dead:beef:cafe:fed9 -- link: enp3s0
                   2604:1580:fe00:0:dead:beef:cafe:fed1 -- link: enp3s0

-- Information acquired via protocol DNS in 75.5ms.
-- Data is authenticated: no; Data was acquired via local or encrypted transport: no
-- Data from: network
Routing...
 1?: [LOCALHOST]                      pmtu 1500
 1:  _gateway (192.168.1.254)                              3.222ms 
 1:  _gateway (192.168.1.254)                              2.671ms 
 2:  104-186-20-1.lightspeed.chrlnc.sbcglobal.net (104.186.20.1)   4.442ms 
 3:  99.144.25.246 (99.144.25.246)                         4.976ms 
 4:  12.240.217.118 (12.240.217.118)                      14.672ms asymm  7 
 5:  12.122.28.154 (12.122.28.154)                        20.591ms asymm  6 
 6:  12.123.138.121 (12.123.138.121)                      12.832ms asymm  5 
 7:  no reply
 8:  uncphillips-to-ws-gw.ncren.net (128.109.1.90)        24.723ms asymm  9 
 9:  core-p-v1213.net.unc.edu (152.2.255.66)              22.923ms asymm 10 
10:  core-m-v1528.net.unc.edu (152.2.255.166)             22.171ms asymm 11 
11:  vm18.fedora.ibiblio.org (152.19.134.198)             24.107ms !H
     Resume: pmtu 1500 
 1?: [LOCALHOST]                        0.004ms pmtu 1500
 1:  no reply
 2:  2001:506:6000:105:76:229:59:241 (2001:506:6000:105:76:229:59:241)   5.079ms 
 3:  2001:506:6000:105:76:229:59:239 (2001:506:6000:105:76:229:59:239)   5.233ms 
 4:  no reply
 5:  be7018.ccr41.atl04.atlas.cogentco.com (2001:550:3::165)  13.269ms asymm  6 
 6:  no reply
 7:  be2690.ccr42.iah01.atlas.cogentco.com (2001:550:0:1000::9a36:1c82)  28.849ms asymm 10 
 8:  no reply
 9:  no reply
10:  no reply
11:  no reply
12:  be2042.ccr21.sea02.atlas.cogentco.com (2001:550:0:1000::9a36:5965)  79.726ms asymm 13 
13:  be2671.ccr21.pdx01.atlas.cogentco.com (2001:550:0:1000::9a36:1f4e)  80.285ms asymm 14 
14:  2001:550:2:1b::a:2 (2001:550:2:1b::a:2)              90.927ms asymm 17 
15:  2605:bc80:f01:11::1 (2605:bc80:f01:11::1)            83.750ms asymm 18 
16:  2605:bc80:f00:1a::2 (2605:bc80:f00:1a::2)            88.660ms asymm 19 
17:  corv-car1-gw.nero.net (2605:bc80:f03:4::2)           82.874ms asymm 15 
18:  proxy06.fedoraproject.org (2605:bc80:3010:600:dead:beef:cafe:fed9)  82.987ms !A
     Resume: pmtu 1500 
Connectivity/quality...
PING  (38.145.60.20) 56(84) bytes of data.

---  ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9010ms
rtt min/avg/max/mdev = 18.608/21.644/26.326/2.524 ms
PING fedoraproject.org(proxy09.fedoraproject.org (2605:bc80:3010:600:dead:beef:cafe:feda)) 56 data bytes

--- fedoraproject.org ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9012ms
rtt min/avg/max/mdev = 82.572/83.627/87.682/1.423 ms
Start: 2021-04-23T20:03:01-0400
HOST: rockhopper                                                                  Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- ???                                                                         100.0    50    0.0   0.0   0.0   0.0   0.0
  2.|-- 2001:506:6000:105:76:229:59:241                                              0.0%    50    4.9   4.8   3.1  11.8   1.5
  3.|-- 2001:506:6000:105:76:229:59:239                                              0.0%    50    5.3   5.2   3.6   9.8   1.4
  4.|-- 2001:1890:f6:4b1::2                                                         22.0%    50   14.9  13.6   9.4  23.8   2.8
  5.|-- 10gigabitethernet3-14.core1.atl1.he.net (2001:470:0:112::1)                 64.0%    50   10.5  10.6   9.1  14.0   1.3
  6.|-- 100ge1-2.core1.ind1.he.net (2001:470:0:5b1::2)                               0.0%    50   28.9  28.7  26.6  33.7   1.9
  7.|-- e0-30.core2.cmh1.he.net (2001:470:0:1a3::1)                                  0.0%    50   35.8  37.2  34.4  50.0   2.8
  8.|-- cpg-ventures-llc.10gigabitethernet3-3.core1.cmh1.he.net (2001:470:1:598::2)  0.0%    50   85.2  35.7  32.9  85.2   7.3
  9.|-- 2604:1580:ff00::34                                                           0.0%    50   33.5  35.2  32.8  52.5   3.0
 10.|-- 2604:1580:fe00:0:dead:beef:cafe:fed1                                         2.0%    50   35.6  35.7  33.0  57.2   3.9

resolvectl flush-caches fixed it once again.

After fix:

NetworkManager...
STATE      CONNECTIVITY  WIFI-HW  WIFI     WWAN-HW  WWAN    
connected  full          enabled  enabled  enabled  enabled 
NAME    UUID                                  TYPE      DEVICE 
enp3s0  2df4c834-7005-3f61-ad19-ddc7a2668f87  ethernet  enp3s0 
Resolver...
Global:
Link 2 (enp3s0): 192.168.1.254 2600:1700:e20:bfb0::1
Global:
Link 2 (enp3s0): attlocal.net
fedoraproject.org: 2605:bc80:3010:600:dead:beef:cafe:fed9 -- link: enp3s0
                   2620:52:3:1:dead:beef:cafe:fed7 -- link: enp3s0
                   2620:52:3:1:dead:beef:cafe:fed6 -- link: enp3s0
                   2610:28:3090:3001:dead:beef:cafe:fed3 -- link: enp3s0
                   2605:bc80:3010:600:dead:beef:cafe:feda -- link: enp3s0
                   2604:1580:fe00:0:dead:beef:cafe:fed1 -- link: enp3s0
                   152.19.134.142              -- link: enp3s0
                   38.145.60.21                -- link: enp3s0
                   67.219.144.68               -- link: enp3s0
                   209.132.190.2               -- link: enp3s0
                   8.43.85.73                  -- link: enp3s0
                   8.43.85.67                  -- link: enp3s0
                   38.145.60.20                -- link: enp3s0
                   140.211.169.206             -- link: enp3s0
                   152.19.134.198              -- link: enp3s0
                   140.211.169.196             -- link: enp3s0

-- Information acquired via protocol DNS in 449us.
-- Data is authenticated: no; Data was acquired via local or encrypted transport: no
-- Data from: cache
Routing...
 1?: [LOCALHOST]                      pmtu 1500
 1:  _gateway (192.168.1.254)                              2.881ms 
 1:  _gateway (192.168.1.254)                              5.336ms 
 2:  104-186-20-1.lightspeed.chrlnc.sbcglobal.net (104.186.20.1)   3.631ms 
 3:  99.144.25.246 (99.144.25.246)                         4.350ms 
 4:  12.240.217.118 (12.240.217.118)                      16.934ms asymm  6 
 5:  ggr2.attga.ip.att.net (12.122.140.93)                 9.492ms 
 6:  192.205.36.238 (192.205.36.238)                       9.891ms 
 7:  be2789.ccr41.atl01.atlas.cogentco.com (154.54.24.249)   9.786ms 
 8:  be2690.ccr42.iah01.atlas.cogentco.com (154.54.28.130)  48.159ms 
 9:  be2443.ccr32.dfw01.atlas.cogentco.com (154.54.44.230)  27.699ms 
10:  be2433.ccr22.mci01.atlas.cogentco.com (154.54.3.214)  39.185ms 
11:  be3035.ccr21.den01.atlas.cogentco.com (154.54.5.89)  48.412ms 
12:  be3037.ccr21.slc01.atlas.cogentco.com (154.54.41.145)  69.444ms 
13:  be2085.ccr21.sea02.atlas.cogentco.com (154.54.2.197)  79.232ms 
14:  be2671.ccr21.pdx01.atlas.cogentco.com (154.54.31.78)  83.706ms 
15:  cogent-pdx.nero.net (38.142.108.50)                 112.486ms asymm 16 
16:  ptck-p1-gw.nero.net (207.98.64.83)                   86.263ms asymm 15 
17:  corv-p1-gw.nero.net (207.98.64.25)                   88.650ms asymm 16 
18:  corv-car1-gw.nero.net (207.98.64.19)                 83.677ms asymm 15 
19:  proxy06.fedoraproject.org (140.211.169.196)          82.699ms !H
     Resume: pmtu 1500 
 1?: [LOCALHOST]                        0.002ms pmtu 1500
 1:  no reply
 2:  2001:506:6000:105:76:229:59:241 (2001:506:6000:105:76:229:59:241)   4.973ms 
 3:  2001:506:6000:105:76:229:59:239 (2001:506:6000:105:76:229:59:239)   4.606ms 
 4:  2001:1890:f6:4b1::2 (2001:1890:f6:4b1::2)            11.527ms asymm  6 
 5:  10gigabitethernet3-14.core1.atl1.he.net (2001:470:0:112::1)  10.709ms asymm  7 
 6:  100ge1-2.core1.ind1.he.net (2001:470:0:5b1::2)       27.281ms asymm 11 
 7:  e0-30.core2.cmh1.he.net (2001:470:0:1a3::1)          36.551ms asymm 12 
 8:  cpg-ventures-llc.10gigabitethernet3-3.core1.cmh1.he.net (2001:470:1:598::2)  35.140ms asymm 13 
 9:  2604:1580:ff00::34 (2604:1580:ff00::34)              34.908ms asymm 14 
10:  2604:1580:fe00:0:dead:beef:cafe:fed1 (2604:1580:fe00:0:dead:beef:cafe:fed1)  37.498ms !A
     Resume: pmtu 1500 
Connectivity/quality...
PING  (8.43.85.73) 56(84) bytes of data.

---  ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9012ms
rtt min/avg/max/mdev = 22.173/23.975/29.782/2.033 ms
PING fedoraproject.org(proxy06.fedoraproject.org (2605:bc80:3010:600:dead:beef:cafe:fed9)) 56 data bytes

--- fedoraproject.org ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9010ms
rtt min/avg/max/mdev = 81.883/82.994/84.273/0.751 ms
Start: 2021-04-23T20:07:57-0400
HOST: rockhopper                                                         Loss%   Snt   Last   Avg  Best  Wrst StDev
  1.|-- ???                                                                100.0    50    0.0   0.0   0.0   0.0   0.0
  2.|-- 2001:506:6000:105:76:229:59:241                                     0.0%    50    3.8   4.1   2.8   7.5   0.9
  3.|-- 2001:506:6000:105:76:229:59:239                                     0.0%    50    5.6   4.9   3.3   9.9   1.2
  4.|-- attga403igs.ipv6.att.net (2001:1890:ff:ffff:12:122:140:93)         62.0%    50   16.0  12.2   9.4  16.0   1.8
  5.|-- be7018.ccr41.atl04.atlas.cogentco.com (2001:550:3::165)            40.0%    50   12.1  11.0   9.5  17.4   1.4
  6.|-- be2848.ccr42.atl01.atlas.cogentco.com (2001:550:0:1000::9a36:675)  74.0%    50   11.6  12.5   9.4  34.9   6.8
  7.|-- be2690.ccr42.iah01.atlas.cogentco.com (2001:550:0:1000::9a36:1c82) 72.0%    50   28.7  28.1  26.8  31.0   1.1
  8.|-- be2443.ccr32.dfw01.atlas.cogentco.com (2001:550:0:1000::9a36:2ce6) 50.0%    50   32.6  31.4  30.1  32.6   0.7
  9.|-- be2433.ccr22.mci01.atlas.cogentco.com (2001:550:0:1000::9a36:3d6)  74.0%    50   37.5  38.2  36.9  40.6   1.1
 10.|-- be3036.ccr22.den01.atlas.cogentco.com (2001:550:0:1000::9a36:1f59) 84.0%    50   51.8  51.5  50.3  54.3   1.3
 11.|-- be3038.ccr32.slc01.atlas.cogentco.com (2001:550:0:1000::9a36:2a61) 48.0%    50   70.0  70.5  68.5  75.3   1.6
 12.|-- be2029.ccr22.sea02.atlas.cogentco.com (2001:550:0:1000::9a36:566e) 70.0%    50   77.1  78.0  77.0  81.2   1.1
 13.|-- be2670.ccr21.pdx01.atlas.cogentco.com (2001:550:0:1000::9a36:2a96) 30.0%    50   80.4  80.8  79.4  82.5   0.7
 14.|-- 2001:550:2:1b::a:2                                                  0.0%    50   84.6  86.3  81.3 172.6  15.5
 15.|-- 2605:bc80:f01:11::1                                                 0.0%    50   83.3  84.4  81.9 115.9   5.3
 16.|-- corv-p1-gw.nero.net (2605:bc80:f00:13::2)                           0.0%    50   87.8  89.4  86.3 121.9   6.2
 17.|-- corv-car1-gw.nero.net (2605:bc80:f03:4::2)                          0.0%    50   83.0  84.2  82.1  93.8   2.2
 18.|-- proxy09.fedoraproject.org (2605:bc80:3010:600:dead:beef:cafe:feda)  0.0%    50   84.2  84.3  81.9 124.2   6.0
1 Like

Is this your main IPv6 provider?
It’s confusing why you have 2 traceroute outputs with different routing paths.

Isn’t it an IPv6 tunnel broker?
It might be a problem with incorrectly configured source routing.

100% packet loss on the first gateway doesn’t seem right.
Looks like a problem with IPv6 firewall configuration on the router.

It’s normal, you have both DNSv4 and DNSv6 here:

However, you may want to replace that resolver with public ones:

sudo nmcli connection modify id enp3s0 \
ipv6.ignore-auto-dns yes \
ipv6.dns 2001:4860:4860::8888,2001:4860:4860::8844
sudo nmcli connection up id enp3s0

Or simply disable the 6in4 tunnel to fix routing.

1 Like

Is 2001:1890:f6:4b1::2 the endpoint of a Hurricane Electric 6to4 tunnel and 2001:506… the subnet assigned by Hurricane? Another traceroute starts with the 2001:506 addresses and jumps to ipv6.att.net. Something unstable in the routing resulting in traffic with unexpected source address?
Recently, I had some conflict with systemd-resolved caching things longer as expected, but in your case, resolvectl shows both a IPv4 and IPv6 nameserver. And if no IPv6 nameserver, the 192.168.1.254 might be able to resolve IPv6 too…
I would start with inspecting the routes, no idea why clearing the cache helps.

I am so confused. I am finally at a point where clearing the cache does nothing, and before going for the good 'ol reboot I checked my logs and found this:
Grace period over, resuming full feature set (UDP+EDNS0) for DNS server 2600:1700:e20:bfb0::1.
and
Using degraded feature set UDP instead of UDP+EDNS0 for DNS server 2600:1700:e20:bfb0::1. when running https://ipv6-test.com/ (and failing it). Is this unrelated or could it be part of the issue? I’m going to try @vgaetera’s idea right now.

when running:

sudo nmcli connection modify id enp3s0 \
ipv6.ignore-auto-dns \
ipv6.dns 2001:4860:4860::8888,2001:4860:4860::8844

I receive the error: Error: failed to modify ipv6.ignore-auto-dns: 'ipv6.dns' is not valid; use [true, yes, on] or [false, no, off].

Is this simply syntax or something else?

nmcli tool, version 1.30.2-1.fc34

sudo nmcli connection modify id enp3s0 \ 
ipv6.ignore-auto-dns true \
ipv6.dns 2001:4860:4860::8888,2001:4860:4860::8844

Seems to have fixed it for now! Hopefully, it stays fixed. What’s weird is I tried using 1.1.1.1 (although through GNOME-settings which may be different) and that didn’t work before… I’m not going to mark as solved just yet as this problem has been extremely unpredictable, and I’ve thought I’ve solved it before, but hopefully things work out.

1 Like

It was a fluke. Things are still very broken after just a few minutes:

NetworkManager...
STATE      CONNECTIVITY  WIFI-HW  WIFI     WWAN-HW  WWAN    
connected  full          enabled  enabled  enabled  enabled 
NAME    UUID                                  TYPE      DEVICE 
enp3s0  2df4c834-7005-3f61-ad19-ddc7a2668f87  ethernet  enp3s0 
Resolver...
Global:
Link 2 (enp3s0): 192.168.1.254
Global:
Link 2 (enp3s0): attlocal.net
fedoraproject.org: 67.219.144.68               -- link: enp3s0
                   38.145.60.21                -- link: enp3s0
                   38.145.60.20                -- link: enp3s0
                   209.132.190.2               -- link: enp3s0
                   140.211.169.206             -- link: enp3s0
                   8.43.85.73                  -- link: enp3s0
                   140.211.169.196             -- link: enp3s0
                   152.19.134.142              -- link: enp3s0
                   152.19.134.198              -- link: enp3s0
                   8.43.85.67                  -- link: enp3s0
                   2605:bc80:3010:600:dead:beef:cafe:feda -- link: enp3s0
                   2620:52:3:1:dead:beef:cafe:fed6 -- link: enp3s0
                   2604:1580:fe00:0:dead:beef:cafe:fed1 -- link: enp3s0
                   2610:28:3090:3001:dead:beef:cafe:fed3 -- link: enp3s0
                   2620:52:3:1:dead:beef:cafe:fed7 -- link: enp3s0
                   2605:bc80:3010:600:dead:beef:cafe:fed9 -- link: enp3s0

-- Information acquired via protocol DNS in 587us.
-- Data is authenticated: no; Data was acquired via local or encrypted transport: no
-- Data from: cache
Routing...
 1?: [LOCALHOST]                      pmtu 1500
 1:  _gateway (192.168.1.254)                              6.193ms 
 1:  _gateway (192.168.1.254)                              3.810ms 
 2:  104-186-20-1.lightspeed.chrlnc.sbcglobal.net (104.186.20.1)  10.077ms 
 3:  99.144.25.246 (99.144.25.246)                         4.739ms 
 4:  12.240.217.118 (12.240.217.118)                      13.684ms asymm  6 
 5:  ggr2.attga.ip.att.net (12.122.140.93)                15.106ms 
 6:  be7018.ccr41.atl04.atlas.cogentco.com (154.54.11.85)  10.318ms 
 7:  be2789.ccr41.atl01.atlas.cogentco.com (154.54.24.249)   9.334ms 
 8:  be2112.ccr41.dca01.atlas.cogentco.com (154.54.7.157)  25.423ms asymm 10 
 9:  be3083.ccr41.iad02.atlas.cogentco.com (154.54.30.54)  25.218ms asymm 10 
10:  38.32.106.90 (38.32.106.90)                          98.735ms asymm 11 
11:  gateway (209.132.185.254)                            99.024ms asymm 13 
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     Too many hops: pmtu 1500
     Resume: pmtu 1500 
 1?: [LOCALHOST]                        0.006ms pmtu 1500
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     Too many hops: pmtu 1500
     Resume: pmtu 1500 
Connectivity/quality...
PING  (38.145.60.20) 56(84) bytes of data.

---  ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9013ms
rtt min/avg/max/mdev = 95.303/107.322/118.179/8.168 ms
PING fedoraproject.org(proxy06.fedoraproject.org (2605:bc80:3010:600:dead:beef:cafe:fed9)) 56 data bytes

--- fedoraproject.org ping statistics ---
10 packets transmitted, 0 received, 100% packet loss, time 9225ms

Start: 2021-04-28T13:44:33-0400
HOST: rockhopper Loss%   Snt   Last   Avg  Best  Wrst StDev

It seems… worse.

I am so very, confused. I realized I have managed to forego the possibly obvious solution of resetting my router, so I am going to do that see where that brings me.

Beyond that, I am at a loss.

1 Like

Try disabling the IPv6 tunnel broker on the router since your ISP already provides a native IPv6.