IPV6 stopped working

Schlaf · March 24, 2021, 4:24pm

Hi everyone,

A few days ago IPV6 stopped working for me.
IPV4 still works fine though.
I have openwrt 19.07.7 running on a Netgear R6220, wich is plugged straight into a DOCSIS modem.

I have already reset both the modem as well as the router to default settings and it didn't help.
My ISP won't offer any advice beyond this ....
The ISP is PYÜR in case anybody happens to be familiar with it.

Strangely enough my router seems to still be assigned an IPV6 prefix via DHCPV6. However I can't ping anything via IPV6.

I would really appreciate some help with troubleshooting this.

Here is the output of an IPV6 ping. Not sure what else you would need to troubleshoot this.

PING openwrt.org (2a03:b0c0:3:d0::1af1:1): 56 data bytes

--- openwrt.org ping statistics ---
5 packets transmitted, 0 packets received, 100% packet loss

dlakelan · March 24, 2021, 4:28pm

Can you show output of

ip addr show

Schlaf · March 24, 2021, 4:32pm

Yep, here's the output:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN qlen 1000
    link/ether 44:a5:6e:70:f5:20 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::46a5:6eff:fe70:f520/64 scope link 
       valid_lft forever preferred_lft forever
5: br-lan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
    link/ether 44:a5:6e:70:f5:20 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.1/24 brd 192.168.2.255 scope global br-lan
       valid_lft forever preferred_lft forever
    inet6 2a02:2454:66c:6400::1/60 scope global dynamic 
       valid_lft 2812sec preferred_lft 2812sec
    inet6 fdb7:6619:5428::1/60 scope global 
       valid_lft forever preferred_lft forever
    inet6 fe80::46a5:6eff:fe70:f520/64 scope link 
       valid_lft forever preferred_lft forever
6: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br-lan state UP qlen 1000
    link/ether 44:a5:6e:70:f5:20 brd ff:ff:ff:ff:ff:ff
7: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
    link/ether 44:a5:6e:70:f5:21 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.69/24 brd 192.168.100.255 scope global eth0.2
       valid_lft forever preferred_lft forever
    inet 100.73.130.118/18 brd 100.73.191.255 scope global eth0.2
       valid_lft forever preferred_lft forever
    inet6 2a02:2454:0:17:a577:476d:9ba6:f5ed/128 scope global dynamic 
       valid_lft 2812sec preferred_lft 2812sec
    inet6 fe80::46a5:6eff:fe70:f521/64 scope link 
       valid_lft forever preferred_lft forever
8: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br-lan state UP qlen 1000
    link/ether 44:a5:6e:70:f5:20 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::46a5:6eff:fe70:f520/64 scope link 
       valid_lft forever preferred_lft forever
9: wlan1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br-lan state UP qlen 1000
    link/ether 44:a5:6e:70:f5:24 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::46a5:6eff:fe70:f524/64 scope link 
       valid_lft forever preferred_lft forever

dlakelan · March 24, 2021, 4:35pm

So your ISP has given you IPv6 addresses and prefixes. So unless you've changed from a default config this should be working. You can try a trace route to see how far your IPv6 connectivity extends

Schlaf · March 24, 2021, 4:45pm

Ok, I ran the following command on my PC:

tracepath -6 openwrt.org

 1?: [LOCALHOST]                        0.003ms pmtu 1500
 1:  2a02-2454-66c-6400--1.dyn6.pyur.net                   0.698ms 
 1:  2a02-2454-66c-6400--1.dyn6.pyur.net                   0.351ms 
 2:  no reply
 3:  no reply
 4:  no reply
 5:  no reply
 6:  no reply
 7:  no reply
 8:  no reply
 9:  no reply

And I ran traceroute6 openwrt.org on my router

traceroute to openwrt.org (2a03:b0c0:3:d0::1af1:1), 30 hops max, 64 byte packets
 1  *  *  *
 2  *  *  *
 3  *  *  *
 4  *  *  *
 5  *  *  *
 6  *  *  *
 7  *  *  *
 8  *  *  *
 9  *  *  *
10  *  *  *
11  *  *  *
12  *  *  *
13  *  *  *
14  *  *  *
15  *  *  *
16  *  *  *
17  *  *  *
18  *  *  *
19  *  *  *
20  *  *  *
21  *  *  *
22  *  *  *
23  *  *  *
24  *  *  *
25  *  *  *
26  *  *  *
27  *  *  *
28  *  *  *
29  *  *  *
30  *  *  *

dlakelan · March 24, 2021, 4:51pm

What does

ip -6 route show

Give?

You have no connectivity beyond your router. It makes me think your router has a messed up route

Schlaf · March 24, 2021, 4:53pm

Running ip -6 route show on my router gives:

default from 2a02:2454:0:17:a577:476d:9ba6:f5ed via fe80::201:5cff:feb3:5846 dev eth0.2  metric 512 
default from 2a02:2454:66c:6400::/56 via fe80::201:5cff:feb3:5846 dev eth0.2  metric 512 
2a02:2454:66c:6400::/64 dev br-lan  metric 1024 
unreachable 2a02:2454:66c:6400::/56 dev lo  metric 2147483647  error -148
fdb7:6619:5428::/64 dev br-lan  metric 1024 
unreachable fdb7:6619:5428::/48 dev lo  metric 2147483647  error -148
fe80::/64 dev eth0  metric 256 
fe80::/64 dev eth0.2  metric 256 
fe80::/64 dev br-lan  metric 256 
fe80::/64 dev wlan0  metric 256 
fe80::/64 dev wlan1  metric 256 
anycast 2a02:2454:66c:6400:: dev br-lan  metric 0 
anycast fdb7:6619:5428:: dev br-lan  metric 0 
anycast fe80:: dev eth0.2  metric 0 
anycast fe80:: dev br-lan  metric 0 
anycast fe80:: dev eth0  metric 0 
anycast fe80:: dev wlan0  metric 0 
anycast fe80:: dev wlan1  metric 0 
ff00::/8 dev eth0  metric 256 
ff00::/8 dev br-lan  metric 256 
ff00::/8 dev eth0.2  metric 256 
ff00::/8 dev wlan0  metric 256 
ff00::/8 dev wlan1  metric 256

dlakelan · March 24, 2021, 5:04pm

Well the routes look ok so long as that link local address of the ISP upstream router is valid. Can you ping from the openwrt

ping -6 fe80::201:5cff:feb3:5846%eth0.2

Schlaf · March 24, 2021, 5:06pm

Running ping -6 fe80::201:5cff:feb3:5846%eth0.2 on the router gives:

PING fe80::201:5cff:feb3:5846%eth0.2 (fe80::201:5cff:feb3:5846%7): 56 data bytes
64 bytes from fe80::201:5cff:feb3:5846: seq=0 ttl=64 time=7.681 ms
64 bytes from fe80::201:5cff:feb3:5846: seq=1 ttl=64 time=7.461 ms
64 bytes from fe80::201:5cff:feb3:5846: seq=2 ttl=64 time=7.071 ms
64 bytes from fe80::201:5cff:feb3:5846: seq=3 ttl=64 time=7.438 ms
64 bytes from fe80::201:5cff:feb3:5846: seq=4 ttl=64 time=7.033 ms
64 bytes from fe80::201:5cff:feb3:5846: seq=5 ttl=64 time=7.693 ms
64 bytes from fe80::201:5cff:feb3:5846: seq=6 ttl=64 time=7.307 ms
64 bytes from fe80::201:5cff:feb3:5846: seq=7 ttl=64 time=7.627 ms
64 bytes from fe80::201:5cff:feb3:5846: seq=8 ttl=64 time=7.007 ms
^C
--- fe80::201:5cff:feb3:5846%eth0.2 ping statistics ---
9 packets transmitted, 9 packets received, 0% packet loss
round-trip min/avg/max = 7.007/7.368/7.693 ms

dlakelan · March 24, 2021, 6:02pm

It's a bit mysterious. Do you have any firewall rules that are non default?

Schlaf · March 24, 2021, 6:22pm

Nope, I didn't touch the firewall settings at all.

Here ist the Output of ip6tables -L just in case you want to see it:

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     all      anywhere             anywhere             /* !fw3 */
input_rule  all      anywhere             anywhere             /* !fw3: Custom input rule chain */
ACCEPT     all      anywhere             anywhere             ctstate RELATED,ESTABLISHED /* !fw3 */
syn_flood  tcp      anywhere             anywhere             tcp flags:FIN,SYN,RST,ACK/SYN /* !fw3 */
zone_lan_input  all      anywhere             anywhere             /* !fw3 */
zone_wan_input  all      anywhere             anywhere             /* !fw3 */

Chain FORWARD (policy DROP)
target     prot opt source               destination         
forwarding_rule  all      anywhere             anywhere             /* !fw3: Custom forwarding rule chain */
ACCEPT     all      anywhere             anywhere             ctstate RELATED,ESTABLISHED /* !fw3 */
zone_lan_forward  all      anywhere             anywhere             /* !fw3 */
zone_wan_forward  all      anywhere             anywhere             /* !fw3 */
reject     all      anywhere             anywhere             /* !fw3 */

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     all      anywhere             anywhere             /* !fw3 */
output_rule  all      anywhere             anywhere             /* !fw3: Custom output rule chain */
ACCEPT     all      anywhere             anywhere             ctstate RELATED,ESTABLISHED /* !fw3 */
zone_lan_output  all      anywhere             anywhere             /* !fw3 */
zone_wan_output  all      anywhere             anywhere             /* !fw3 */

Chain forwarding_lan_rule (1 references)
target     prot opt source               destination         

Chain forwarding_rule (1 references)
target     prot opt source               destination         

Chain forwarding_wan_rule (1 references)
target     prot opt source               destination         

Chain input_lan_rule (1 references)
target     prot opt source               destination         

Chain input_rule (1 references)
target     prot opt source               destination         

Chain input_wan_rule (1 references)
target     prot opt source               destination         

Chain output_lan_rule (1 references)
target     prot opt source               destination         

Chain output_rule (1 references)
target     prot opt source               destination         

Chain output_wan_rule (1 references)
target     prot opt source               destination         

Chain reject (3 references)
target     prot opt source               destination         
REJECT     tcp      anywhere             anywhere             /* !fw3 */ reject-with tcp-reset
REJECT     all      anywhere             anywhere             /* !fw3 */ reject-with icmp6-port-unreachable

Chain syn_flood (1 references)
target     prot opt source               destination         
RETURN     tcp      anywhere             anywhere             tcp flags:FIN,SYN,RST,ACK/SYN limit: avg 25/sec burst 50 /* !fw3 */
DROP       all      anywhere             anywhere             /* !fw3 */

Chain zone_lan_dest_ACCEPT (4 references)
target     prot opt source               destination         
ACCEPT     all      anywhere             anywhere             /* !fw3 */

Chain zone_lan_forward (1 references)
target     prot opt source               destination         
forwarding_lan_rule  all      anywhere             anywhere             /* !fw3: Custom lan forwarding rule chain */
zone_wan_dest_ACCEPT  all      anywhere             anywhere             /* !fw3: Zone lan to wan forwarding policy */
zone_lan_dest_ACCEPT  all      anywhere             anywhere             /* !fw3 */

Chain zone_lan_input (1 references)
target     prot opt source               destination         
input_lan_rule  all      anywhere             anywhere             /* !fw3: Custom lan input rule chain */
zone_lan_src_ACCEPT  all      anywhere             anywhere             /* !fw3 */

Chain zone_lan_output (1 references)
target     prot opt source               destination         
output_lan_rule  all      anywhere             anywhere             /* !fw3: Custom lan output rule chain */
zone_lan_dest_ACCEPT  all      anywhere             anywhere             /* !fw3 */

Chain zone_lan_src_ACCEPT (1 references)
target     prot opt source               destination         
ACCEPT     all      anywhere             anywhere             ctstate NEW,UNTRACKED /* !fw3 */

Chain zone_wan_dest_ACCEPT (2 references)
target     prot opt source               destination         
DROP       all      anywhere             anywhere             ctstate INVALID /* !fw3: Prevent NAT leakage */
ACCEPT     all      anywhere             anywhere             /* !fw3 */

Chain zone_wan_dest_REJECT (1 references)
target     prot opt source               destination         
reject     all      anywhere             anywhere             /* !fw3 */

Chain zone_wan_forward (1 references)
target     prot opt source               destination         
forwarding_wan_rule  all      anywhere             anywhere             /* !fw3: Custom wan forwarding rule chain */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp echo-request limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Forward */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp echo-reply limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Forward */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp destination-unreachable limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Forward */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp packet-too-big limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Forward */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp time-exceeded limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Forward */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp bad-header limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Forward */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp unknown-header-type limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Forward */
zone_lan_dest_ACCEPT  esp      anywhere             anywhere             /* !fw3: Allow-IPSec-ESP */
zone_lan_dest_ACCEPT  udp      anywhere             anywhere             udp dpt:isakmp /* !fw3: Allow-ISAKMP */
zone_wan_dest_REJECT  all      anywhere             anywhere             /* !fw3 */

Chain zone_wan_input (1 references)
target     prot opt source               destination         
input_wan_rule  all      anywhere             anywhere             /* !fw3: Custom wan input rule chain */
ACCEPT     udp      fc00::/6             fc00::/6             udp dpt:dhcpv6-client /* !fw3: Allow-DHCPv6 */
ACCEPT     ipv6-icmp    fe80::/10            anywhere             ipv6-icmptype 130 code 0 /* !fw3: Allow-MLD */
ACCEPT     ipv6-icmp    fe80::/10            anywhere             ipv6-icmptype 131 code 0 /* !fw3: Allow-MLD */
ACCEPT     ipv6-icmp    fe80::/10            anywhere             ipv6-icmptype 132 code 0 /* !fw3: Allow-MLD */
ACCEPT     ipv6-icmp    fe80::/10            anywhere             ipv6-icmptype 143 code 0 /* !fw3: Allow-MLD */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp echo-request limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Input */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp echo-reply limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Input */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp destination-unreachable limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Input */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp packet-too-big limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Input */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp time-exceeded limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Input */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp bad-header limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Input */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp unknown-header-type limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Input */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp router-solicitation limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Input */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp neighbour-solicitation limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Input */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp router-advertisement limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Input */
ACCEPT     ipv6-icmp    anywhere             anywhere             ipv6-icmp neighbour-advertisement limit: avg 1000/sec burst 5 /* !fw3: Allow-ICMPv6-Input */
zone_wan_src_REJECT  all      anywhere             anywhere             /* !fw3 */

Chain zone_wan_output (1 references)
target     prot opt source               destination         
output_wan_rule  all      anywhere             anywhere             /* !fw3: Custom wan output rule chain */
zone_wan_dest_ACCEPT  all      anywhere             anywhere             /* !fw3 */

Chain zone_wan_src_REJECT (1 references)
target     prot opt source               destination         
reject     all      anywhere             anywhere             /* !fw3 */

dlakelan · March 24, 2021, 6:30pm

Have you tried tcpdump on eth0.2 while pinging from your LAN to an IPv6 host on internet?

Schlaf · March 24, 2021, 6:59pm

I ran tcpdump ip6 -i eth0.2 on my router, while running ping -6 openwrt.org on my PC.
I am not super good at interpreting the output of tcpdump. However as far as I can tell I really just get nothing back after I send a Ping.
Here is a snippet from the tcpdump output:

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0.2, link-type EN10MB (Ethernet), capture size 262144 bytes
18:50:27.161190 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.49744 > fra16s53-in-x03.1e100.net.80: Flags [S], seq 1876179142, win 64800, options [mss 1440,sackOK,TS val 1004161651 ecr 0,nop,wscale 7], length 0
18:50:27.163966 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.18035 > dns.quad9.net.53: 24760+ PTR? 3.0.0.2.0.0.0.0.0.0.0.0.0.0.0.0.3.1.8.0.1.0.0.4.0.5.4.1.0.0.a.2.ip6.arpa. (90)
18:50:27.164097 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.18035 > dns9.quad9.net.53: 24760+ PTR? 3.0.0.2.0.0.0.0.0.0.0.0.0.0.0.0.3.1.8.0.1.0.0.4.0.5.4.1.0.0.a.2.ip6.arpa. (90)
18:50:28.867645 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.49758 > fra16s53-in-x03.1e100.net.80: Flags [S], seq 1122056969, win 64800, options [mss 1440,sackOK,TS val 1004163358 ecr 0,nop,wscale 7], length 0
18:50:34.567933 IP6 fe80::201:5cff:feb3:5846 > ip6-allnodes: ICMP6, router advertisement, length 16
18:50:34.670294 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 1, length 64
18:50:35.694351 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 2, length 64
18:50:36.707568 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 3, length 64
18:50:37.720890 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 4, length 64
18:50:38.734210 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 5, length 64
18:50:39.747551 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 6, length 64
18:50:40.760892 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 7, length 64
18:50:40.814200 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.59544 > 2600:9000:20e8:e000:9:674:7440:21.443: Flags [S], seq 2195815743, win 64800, options [mss 1440,sackOK,TS val 1441333777 ecr 0,nop,wscale 7], length 0
18:50:41.777529 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 8, length 64
18:50:42.524193 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.36398 > 2606:4700::6810:467d.443: Flags [S], seq 2006265534, win 64800, options [mss 1440,sackOK,TS val 2520524439 ecr 0,nop,wscale 7], length 0
18:50:42.524294 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.36396 > 2606:4700::6810:467d.443: Flags [S], seq 208564247, win 64800, options [mss 1440,sackOK,TS val 2520524439 ecr 0,nop,wscale 7], length 0
18:50:42.524366 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.36394 > 2606:4700::6810:467d.443: Flags [S], seq 3550109684, win 64800, options [mss 1440,sackOK,TS val 2520524439 ecr 0,nop,wscale 7], length 0
18:50:42.524436 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.36392 > 2606:4700::6810:467d.443: Flags [S], seq 1622208860, win 64800, options [mss 1440,sackOK,TS val 2520524439 ecr 0,nop,wscale 7], length 0
18:50:42.787512 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 9, length 64
18:50:43.800908 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 10, length 64
18:50:44.557831 IP6 fe80::201:5cff:feb3:5846 > ip6-allnodes: ICMP6, router advertisement, length 16
18:50:44.814175 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 11, length 64
18:50:45.827502 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 12, length 64
18:50:46.840825 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 13, length 64
18:50:47.767579 IP6 fe80::201:5cff:feb3:5846 > ip6-allnodes: ICMP6, router advertisement, length 16
18:50:47.854146 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 14, length 64
18:50:48.867589 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 15, length 64
18:50:49.880793 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 16, length 64
18:50:50.386110 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.40593 > dns.quad9.net.53: 46007+ A? detectportal.firefox.com. (42)
18:50:50.386288 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.40593 > dns9.quad9.net.53: 46007+ A? detectportal.firefox.com. (42)
18:50:50.403833 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.55844 > 2600:1901:0:38d7::.80: Flags [S], seq 932203422, win 64800, options [mss 1440,sackOK,TS val 1233124656 ecr 0,nop,wscale 7], length 0
18:50:50.654990 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.55846 > 2600:1901:0:38d7::.80: Flags [S], seq 3155687960, win 64800, options [mss 1440,sackOK,TS val 1233124908 ecr 0,nop,wscale 7], length 0
18:50:50.894090 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 17, length 64
18:50:50.907761 IP6 fe80::201:5cff:feb3:5846 > ip6-allnodes: ICMP6, router advertisement, length 16
18:50:51.427450 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.55844 > 2600:1901:0:38d7::.80: Flags [S], seq 932203422, win 64800, options [mss 1440,sackOK,TS val 1233125680 ecr 0,nop,wscale 7], length 0
18:50:51.667414 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.55846 > 2600:1901:0:38d7::.80: Flags [S], seq 3155687960, win 64800, options [mss 1440,sackOK,TS val 1233125920 ecr 0,nop,wscale 7], length 0
18:50:51.907475 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 18, length 64
18:50:52.528567 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.23522 > dns.quad9.net.53: 36786+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:52.528703 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.23522 > dns9.quad9.net.53: 36786+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:52.560136 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.54273 > dns.quad9.net.53: 42385+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:52.560313 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.54273 > dns9.quad9.net.53: 42385+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:52.596004 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.46710 > dns.quad9.net.53: 30474+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:52.596135 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.46710 > dns9.quad9.net.53: 30474+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:52.920802 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 19, length 64
18:50:52.922399 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.16543 > dns.quad9.net.53: 21525+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:52.922518 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.16543 > dns9.quad9.net.53: 21525+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:52.952149 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.57055 > dns.quad9.net.53: 59959+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:52.952281 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.57055 > dns9.quad9.net.53: 59959+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:52.984042 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.35803 > dns.quad9.net.53: 4841+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:52.984167 IP6 2a02-2454-66c-6400--1.dyn6.pyur.net.35803 > dns9.quad9.net.53: 4841+ PTR? 0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.d.8.3.0.0.0.0.1.0.9.1.0.0.6.2.ip6.arpa. (90)
18:50:53.614096 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.55844 > 2600:1901:0:38d7::.80: Flags [S], seq 932203422, win 64800, options [mss 1440,sackOK,TS val 1233127867 ecr 0,nop,wscale 7], length 0
18:50:53.827397 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.55846 > 2600:1901:0:38d7::.80: Flags [S], seq 3155687960, win 64800, options [mss 1440,sackOK,TS val 1233128080 ecr 0,nop,wscale 7], length 0
18:50:53.934037 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 20, length 64
18:50:54.467400 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.55722 > 2600:1901:0:38d7::.80: Flags [S], seq 3387917429, win 64800, options [mss 1440,sackOK,TS val 1233128720 ecr 0,nop,wscale 7], length 0
18:50:54.947377 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net > wiki-01.infra.openwrt.org: ICMP6, echo request, seq 21, length 64
18:50:55.657943 IP6 fe80::201:5cff:feb3:5846 > ip6-allnodes: ICMP6, router advertisement, length 16
18:50:57.667413 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.55844 > 2600:1901:0:38d7::.80: Flags [S], seq 932203422, win 64800, options [mss 1440,sackOK,TS val 1233131920 ecr 0,nop,wscale 7], length 0
18:50:57.884087 IP6 2a02-2454-66c-6400-8038-a3fb-60e7-53f6.dyn6.pyur.net.55846 > 2600:1901:0:38d7::.80: Flags [S], seq 3155687960, win 64800, options [mss 1440,sackOK,TS val 1233132137 ecr 0,nop,wscale 7], length 0
^C
58 packets captured
61 packets received by filter
0 packets dropped by kernel

dlakelan · March 24, 2021, 7:03pm

yep, the only thing I see coming from anything other than your network is the router advertisements.

It's time to complain to your ISP. Tell them you can clearly see your network sending IPv6 packets towards them, but zero packets other than the router adverts are returning.

Schlaf · March 24, 2021, 7:13pm

I will have to call them tomorrow.
Just ran tcpdump on a server that I am renting. The ping actually gets there and my server sends a reply.
The reply just never gets back to my router.

Thank you so much for your help.

Oh, and should this topic be marked as solved now?

dlakelan · March 24, 2021, 7:16pm

Oh good. It's clear the ISP is screwing up. With those pieces of information (that you are sending successfully, that your server on the Internet receives it, and that no packets come back to your router) you should be able to get a resolution from them.

I'd suggest that you wait for the reply from your ISP and then write up what happened and mark that as the solution.

Schlaf · March 25, 2021, 6:59pm

Well, I called my ISP and they are of the opinion, that this is not their problem.

When I called them today, they switched my router from bridge mode back into router mode (is that what it is called?).
Once their internet box was doing the routing, IPV6 worked normally. They don't offer tech support for openwrt -> case closed.

I might try to complain once more tomorrow, but I think it will be hard to get more that shrug out of them...

dlakelan · March 25, 2021, 7:06pm

Switch the modem back to bridge mode and see if the problem is still there?

My guess is their piece of garbage equipment has a borken bridge mode

Schlaf · March 25, 2021, 7:12pm

It is in bridge mode again now.
The behaviour is still the same. The bridge mode probably is broken.

One bit of info they gave me was that they had replaced their DHCP servers on the day that my IPV6 stopped working. Not sure how that would break bridge mode, but not DHCP.

Maybe I will ask them for a new internet box tomorrow. Perhaps that will work.
The one I use has not received a firmware update since 2014.

dlakelan · March 25, 2021, 7:16pm

I bet that will help a lot. If this is a cable modem you could also buy one for yourself. Get a modem only device