[SOLVED] Cannot Ping IPv6 Addresses.

nourathar · 2023-08-27 13:38:55

Moderator [ewaller] split from https://bbs.archlinux.org/viewtopic.php?id=287536
Was this resolved and how ?

I am wondering if I have the same issue: since a recent update, ping doesn't work anymore and I realized that this happens because it defaults to using ipv6 but ipv6 doesn't actually work. Some other terminal commands seem to default to ipv6 too, so those have similar problems.

so ping -4 works fine

ping -4 google.com
PING  (142.250.179.142) 56(84) bytes of data.
64 bytes from ams17s10-in-f14.1e100.net (142.250.179.142): icmp_seq=1 ttl=57 time=20.1 ms
64 bytes from ams17s10-in-f14.1e100.net (142.250.179.142): icmp_seq=2 ttl=57 time=15.0 ms
64 bytes from ams17s10-in-f14.1e100.net (142.250.179.142): icmp_seq=3 ttl=57 time=16.2 ms
64 bytes from ams17s10-in-f14.1e100.net (142.250.179.142): icmp_seq=4 ttl=57 time=19.0 ms
64 bytes from ams17s10-in-f14.1e100.net (142.250.179.142): icmp_seq=5 ttl=57 time=13.5 ms
64 bytes from ams17s10-in-f14.1e100.net (142.250.179.142): icmp_seq=6 ttl=57 time=17.2 ms
64 bytes from ams17s10-in-f14.1e100.net (142.250.179.142): icmp_seq=7 ttl=57 time=18.6 ms
^C
---  ping statistics ---
7 packets transmitted, 7 received, 0% packet loss, time 6009ms
rtt min/avg/max/mdev = 13.537/17.069/20.090/2.158 ms

whereas ping -6 doesn't:

ping -6 2a03:4000:28:365::1
PING 2a03:4000:28:365::1(2a03:4000:28:365::1) 56 data bytes
^C
--- 2a03:4000:28:365::1 ping statistics ---
102 packets transmitted, 0 received, 100% packet loss, time 102341ms

the output of my "ip -6 a" is similar as the OP, this is a desktop machine in a home ethernet network and I only use dhcpd, which is also similar to the OP.

Last edited by nourathar (2023-08-28 08:02:29)

seth · 2023-08-27 13:41:13

the output of my "ip -6 a" is similar as the OP

-thc wrote:

Because your network stack has/acquires an ULA address (fd00::/16) IPv6 is working.
Your problem is the connectivity beyond link-local and ULA addresses.
ULA addresses will not be used for access beyond your router.

I only use dhcpd, which is also similar to the OP

seth wrote:

when it looks like you've a carrier, run "dhcpcd -dB" (it'll not fork), wait a minute (get a cup of coffee) and post the output of that as well

nourathar · 2023-08-27 13:57:00

I only use dhcpd, which is also similar to the OP

seth wrote:

when it looks like you've a carrier, run "dhcpcd -dB" (it'll not fork), wait a minute (get a cup of coffee) and post the output of that as well

Hi Seth, thanks for the reply, here some of that output, is this enough ?

$ sudo dhcpcd -dB
dhcpcd-10.0.2 starting
udev: starting
dev: loaded udev
spawned privileged proxy on PID 9831
spawned network proxy on PID 9832
spawned controller proxy on PID 9833
DUID 00:01:00:01:22:29:bf:ec:14:da:e9:f5:de:33
sandbox: seccomp
lo: ignoring due to interface type and no config
enp3s0: executing: /usr/lib/dhcpcd/dhcpcd-run-hooks PREINIT
enp3s0: executing: /usr/lib/dhcpcd/dhcpcd-run-hooks CARRIER
enp3s0: IAID e9:f5:de:33
enp3s0: delaying IPv6 router solicitation for 0.1 seconds
enp3s0: delaying IPv4 for 0.6 seconds
enp3s0: soliciting an IPv6 router
enp3s0: sending Router Solicitation
enp3s0: Router Advertisement from fe80::6802:b8ff:fe25:7fc1
enp3s0: adding address 2a02:1811:xxxx:xxxx:1aff:5fc6:326e:ba34/64
enp3s0: pltime 86400 seconds, vltime 216508 seconds
enp3s0: adding route to 2a02:1811:xxxx:xxxx:1aff:5fc6:326e:ba34/64
enp3s0: waiting for Router Advertisement DAD to complete
enp3s0: requesting DHCPv6 information
enp3s0: delaying INFORM6 (xid 0x281bcc), next in 1.1 seconds
enp3s0: adding default route via fe80::6802:b8ff:fe25:7fc1
enp3s0: reading lease: /var/lib/dhcpcd/enp3s0.lease
enp3s0: soliciting a DHCP lease
enp3s0: spawned BPF BOOTP on PID 9836
enp3s0: sending DISCOVER (xid 0x7b5a5306), next in 3.6 seconds
enp3s0: multicasting INFORM6 (xid 0x281bcc), next in 1.0 seconds
enp3s0: REPLY6 received from fe80::6802:b8ff:fe25:7fc1
enp3s0: refresh in 86400 seconds
enp3s0: writing lease: /var/lib/dhcpcd/enp3s0.lease6
enp3s0: executing: /usr/lib/dhcpcd/dhcpcd-run-hooks INFORM6
enp3s0: Router Advertisement DAD completed
enp3s0: executing: /usr/lib/dhcpcd/dhcpcd-run-hooks ROUTERADVERT
enp3s0: sending NA for 2a02:1811:xxxx:xxxx:1aff:5fc6:326e:ba34/64
enp3s0: sending NA for 2a02:1811:xxxx:xxxx:1aff:5fc6:326e:ba34/64
enp3s0: offered 192.168.0.181 from 192.168.0.1
enp3s0: process BPF BOOTP already started on pid 9836
enp3s0: sending REQUEST (xid 0x7b5a5306), next in 4.5 seconds
enp3s0: acknowledged 192.168.0.181 from 192.168.0.1
enp3s0: spawned BPF ARP 192.168.0.181 on PID 9962
enp3s0: probing address 192.168.0.181/24
enp3s0: probing for 192.168.0.181
enp3s0: ARP probing 192.168.0.181 (1 of 3), next in 2.0 seconds
enp3s0: sending NA for 2a02:1811:xxxx:xxxx:1aff:5fc6:326e:ba34/64
enp3s0: ARP probing 192.168.0.181 (2 of 3), next in 1.6 seconds
enp3s0: ARP probing 192.168.0.181 (3 of 3), next in 2.0 seconds
enp3s0: DAD completed for 192.168.0.181
enp3s0: leased 192.168.0.181 for 3600 seconds
enp3s0: renew in 1800 seconds, rebind in 3150 seconds
enp3s0: writing lease: /var/lib/dhcpcd/enp3s0.lease
enp3s0: adding IP address 192.168.0.181/24 broadcast 192.168.0.255
enp3s0: adding route to 192.168.0.0/24
enp3s0: adding default route via 192.168.0.1
enp3s0: ARP announcing 192.168.0.181 (1 of 2), next in 2.0 seconds
enp3s0: executing: /usr/lib/dhcpcd/dhcpcd-run-hooks BOUND
enp3s0: BPF BOOTP exited from PID 9836
enp3s0: ARP announcing 192.168.0.181 (2 of 2)
enp3s0: Router Advertisement from fe80::6802:b8ff:fe25:7fc1
enp3s0: adding address 2a02:1811:xxxx:xxxx:1aff:5fc6:326e:ba34/64
enp3s0: pltime 86400 seconds, vltime 216508 seconds
enp3s0: sending NA for 2a02:1811:xxxx:xxxx:1aff:5fc6:326e:ba34/64
enp3s0: executing: /usr/lib/dhcpcd/dhcpcd-run-hooks ROUTERADVERT
enp3s0: requesting DHCPv6 information
enp3s0: delaying INFORM6 (xid 0x7f73ef), next in 1.0 seconds
enp3s0: sending NA for 2a02:1811:xxxx:xxxx:1aff:5fc6:326e:ba34/64
enp3s0: multicasting INFORM6 (xid 0x7f73ef), next in 1.0 seconds
enp3s0: REPLY6 received from fe80::6802:b8ff:fe25:7fc1
enp3s0: refresh in 86400 seconds
enp3s0: writing lease: /var/lib/dhcpcd/enp3s0.lease6
enp3s0: executing: /usr/lib/dhcpcd/dhcpcd-run-hooks INFORM6
enp3s0: sending NA for 2a02:1811:xxxx:xxxx:1aff:5fc6:326e:ba34/64

There is stuff about about a lease6, but also 'NA', but I don't know that all of that really means...

Last edited by nourathar (2023-08-27 16:05:26)

seth · 2023-08-27 14:09:03

What's the actual "ip a" output?
It looks like you're getting an IP from 2a02:1811::/33 (Belgian Telnet)

Can you

ping 2001:4860:4860::8888 # google's IPv6 DNS

nourathar · 2023-08-27 14:15:03

ip -a is:

$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default 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 noprefixroute 
       valid_lft forever preferred_lft forever
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 14:da:e9:f5:de:33 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.181/24 brd 192.168.0.255 scope global dynamic noprefixroute enp3s0
       valid_lft 2563sec preferred_lft 2113sec
    inet6 2a02:1811:341b:xxxx:xxxx:5fc6:326e:ba34/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 216484sec preferred_lft 86376sec
    inet6 fe80::9de:88ab:891d:1b43/64 scope link 
       valid_lft forever preferred_lft forever

and that ping doesn't work. When I use ping -6 it seems to show a ipv6 addres, so I concluced that ipv6 DNS resolution was not the problem.

$ ping 2001:4860:4860::8888
PING 2001:4860:4860::8888(2001:4860:4860::8888) 56 data bytes
^C
--- 2001:4860:4860::8888 ping statistics ---
151 packets transmitted, 0 received, 100% packet loss, time 152005ms

Last edited by nourathar (2023-08-27 16:05:55)

seth · 2023-08-27 14:21:01

That's not an ULA next the LLA,
https://en.wikipedia.org/wiki/Unique_local_address
https://en.wikipedia.org/wiki/Link-local_address

you're not in the same position as the OP, please report your first post to be split off into its own topic and test

tracepath -6 2001:4860:4860::8888

Do you run a firewall?

nourathar · 2023-08-27 14:46:38

seth wrote:

That's not an ULA next the LLA,
https://en.wikipedia.org/wiki/Unique_local_address
https://en.wikipedia.org/wiki/Link-local_address

aha, thanks, I learned something.

But it when looking into the settings of my modem/router, it seems the address given by ip a corresponds to what my ISP lists behind LAN - subnet IPv6:
Its settings are:

LAN - subnet 192.168.0.1
LAN - subnet IPv6 2a02:1811:341b:3600::/64

So that seems to be a non-standard address range if I understood those links you posted correctly ?

seth wrote:

you're not in the same position as the OP, please report your first post to be split off into its own topic and test
tracepath -6 2001:4860:4860::8888
Do you run a firewall?

I reported that post...

the tracepath gives:

$ tracepath -6 2001:4860:4860::8888
 1?: [LOCALHOST]                        0.013ms pmtu 1500
 1:  ptr-98t722t9a77id83h3nl.18120a2.ip6.access.telenet.be   1.195ms 
 1:  ptr-98t722t9a77id83h3nl.18120a2.ip6.access.telenet.be   2.095ms 
 2:  no reply
 3:  no reply

until it runs out of steam...

There's a firewall in the router, I am using its standard ipv4 settings and it has separate standard settings for ipv6 too. These appear to be active so it shouldn't be blocking all ipv6.
Temporarily switching off the ipv6 firewall doesn't make any difference to what happens with the tracepath command above or for any ping -6.

Last edited by nourathar (2023-08-27 15:12:08)

seth · 2023-08-27 15:13:01

Can you ping 2001:4860:4860::8888 from within the router or other devices behind the same router?

nourathar · 2023-08-27 16:02:57

seth wrote:

Can you ping 2001:4860:4860::8888 from within the router or other devices behind the same router?

ah, no, I have a Debian install that shows the same problems.
So I suppose that makes it very unlikely this is Arch-related and I may need to figure this out with my ISP. Perhaps the only thing that changed is that ping and some other commands now use ipv6 by default, which is why I started noticing ?

Last edited by nourathar (2023-08-27 16:07:47)

seth · 2023-08-27 18:30:12

You might also only now get an IPv6 lease from your ISP, try to simply deactivate it if it only causes you trouble, https://wiki.archlinux.org/title/IPv6#Disable_IPv6

nourathar · 2023-08-28 08:01:56

seth wrote:

You might also only now get an IPv6 lease from your ISP, try to simply deactivate it if it only causes you trouble, https://wiki.archlinux.org/title/IPv6#Disable_IPv6

Aha, that could also be, indeed.
Anyway, thanks a lot for the help and I am marking this as solved since it is not Arch-related.

Last edited by nourathar (2023-08-28 08:03:33)

mwohah · 2023-09-14 18:26:07

I came here because I'm experiencing similar problems also since around Monday or so, but I only updated last Friday so there might be some dependency that broke something.

I also use Telenet and they had problems in my street a few days ago, so at first I figured it was related to that, but then I realized I had strange hangs on some sites since Monday already - servers that happened to support IPv6 and it is being preferred over IPv4 because according to NetworkManager the IPv6 connection is properly 'up'. Also, I have another Debian device running in the same network which can ping over IPv6 just fine, so the routing from the ISP side seems fine.

On my problematic Arch box, I'm getting a global IPv6 address assigned correctly from the ISP/DHCP server, but pinging anything fails with the well-known 'Network is unreachable' error. Earlier today I could still ping the other Debian device in my local network over IPv6, but that also seems to have died due to some unknown reason now.

EDIT: For what it's worth, pinging localhost or my own IPv6 global address seems to work - anywhere else, inside or outside the local network is botched, though.

Last edited by mwohah (2023-09-14 18:33:34)

-thc · 2023-09-15 05:26:32

Please either ask the moderators to split your post from this thread or open a new thread.

mwohah · 2023-09-15 08:44:44

-thc wrote:

Please either ask the moderators to split your post from this thread or open a new thread.

(I might still do that because I also have problems, but) I mainly posted here specifically because I have new information pertaining or relevant to the OP's post, which arguably doesn't belong in a new thread. In other words, it doesn't sound like a coincidence that the OP is experiencing almost identical symptoms around the same time I am, and also happens to have the same ISP.

I realize the topic has been marked as solved, but whilst the proposed fix of turning it off may be acceptable to the author, they may still be interested in knowing that there potentially is another underlying (potentially Arch-specific after all) problem here - and by consequence it might be possible to solve the original problem in a better way.

-thc · 2023-09-15 12:29:48

The TO posted

nourathar wrote:

ah, no, I have a Debian install that shows the same problems.
So I suppose that makes it very unlikely this is Arch-related and I may need to figure this out with my ISP.

and you posted

mwohah wrote:

Also, I have another Debian device running in the same network which can ping over IPv6 just fine, so the routing from the ISP side seems fine.

- which is the opposite.

This leads me to believe your problem may be unrelated.

mwohah · 2023-09-15 15:54:32

I've created a new topic as suggested for my problem. The symptoms are indeed not exactly the same (hence 'almost identical'), but I still feel there is too much overlap for these two problems to not be related - e.g. perhaps the OP didn't test properly on their other device or has IPv6 on it also misconfigured. In any case, I will stop polluting this thread with my problem as suggested. (If the OP also believes the problems are related, they can always view or participate in the new post.)

Arch Linux

#1 2023-08-27 13:38:55

[SOLVED] Cannot Ping IPv6 Addresses.

#2 2023-08-27 13:41:13

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#3 2023-08-27 13:57:00

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#4 2023-08-27 14:09:03

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#5 2023-08-27 14:15:03

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#6 2023-08-27 14:21:01

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#7 2023-08-27 14:46:38

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#8 2023-08-27 15:13:01

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#9 2023-08-27 16:02:57

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#10 2023-08-27 18:30:12

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#11 2023-08-28 08:01:56

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#12 2023-09-14 18:26:07

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#13 2023-09-15 05:26:32

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#14 2023-09-15 08:44:44

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#15 2023-09-15 12:29:48

Re: [SOLVED] Cannot Ping IPv6 Addresses.

#16 2023-09-15 15:54:32

Re: [SOLVED] Cannot Ping IPv6 Addresses.

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