[Solved itself] Can't reach IPv6 addresses over the internet

freyr · 2017-06-30 15:57:15

Hi!

I have a weird problem.
There's a webserver I'm using, web566.webfaction.com. Everything was fine until recently. Today I wanted to connect to it over FTP but I couldn't. I used FileZilla and it tried to connect using the server's IPv6 address. Now, that shouldn't be a problem, but it timed out. I tried to ping the server's URL, again I got the IPv6 address but it timed out. I'm using my modem/router as the DNS server which uses my ISP's DNS servers so obviously if those return an IPv6 address it shouldn't be a problem. Should it?

Since the webserver has an IPv4 address, I tried that, too, and it worked. Next stop was ipv6.google.com in the browser which also timed out. I tried pinging Google's IPv6 address but it timed out.
The only IPv6 I can ping is the localhost, the multicast address and the ULA.

Tracerouter on the other hand gave me a nice route to the webserver using it's IPv4 address. The ftp in the command line also sees its IPv4 address although it tries to connect using the IPv6 at first. This means even though the first I got is IPv6, the DNS server does return the IPv4 address, too.

I tried tracerouter -6 both with the webserver and google.com but it returned only asterisks.

I bypassed my router and connected to the internet using my phone. Everything involving IPv6 resulted in a "Network unreachable" message so I didn't get smarter with that.

My modem/router is a Speedport W 724V, under the IP Address Information (Internet) it says it has IPv6 address range assigned, it has usable address range for LAN, it has GUA, gateway and DNS server address. Seemingly nothing's missing there.

So, what can I do to discover where's the problem and how to fix it? I don't have any other PC on this network at the moment so I can't try that, and my phone, although Android, doesn't really likes IPv6, every app that can do anything with it crashes.

Note that I disabled my firewall (ufw) and reset iptables using a script before I tried searching for the problem.

Last edited by freyr (2017-07-02 10:34:19)

Lone_Wolf · 2017-06-30 18:30:27

please post route -4 and route -6 output .

freyr · 2017-06-30 20:41:20

Lone_Wolf wrote:

please post route -4 and route -6 output .

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         speedport.ip    0.0.0.0         UG    100    0        0 enp3s0
192.168.1.0     0.0.0.0         255.255.255.0   U     100    0        0 enp3s0

Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
20014C4E138962450000000000000000.dsl.pool.telekom.hu/64 [::]                       U    100 0     0 enp3s0
20014C4E138962450000000000000000.dsl.pool.telekom.hu/64 [::]                       U    202 0     0 enp3s0
20014C4E138962470000000000000000.dsl.pool.telekom.hu/64 [::]                       U    100 0     0 enp3s0
20014C4E138962470000000000000000.dsl.pool.telekom.hu/64 [::]                       U    202 0     0 enp3s0
fd4a:ca1:7e60:1::/64           [::]                       U    100 0     0 enp3s0
fd4a:ca1:7e60:1::/64           [::]                       U    202 0     0 enp3s0
speedport.ip/128               [::]                       U    100 0     0 enp3s0
fe80::/64                      [::]                       U    256 1     1 enp3s0
[::]/0                         speedport.ip               UG   100 2     2 enp3s0
[::]/0                         [::]                       !n   -1  1  9236 lo
localhost.localdomain/128      [::]                       Un   0   3    39 lo
20014C4E13896245022522FFFEEC4DAE.dsl.pool.telekom.hu/128 [::]                       Un   0   1     0 lo
20014C4E13896245FCF5237D99C48075.dsl.pool.telekom.hu/128 [::]                       Un   0   1     0 lo
20014C4E13896247022522FFFEEC4DAE.dsl.pool.telekom.hu/128 [::]                       Un   0   1     0 lo
20014C4E138962479DFFDF97A3AF08A1.dsl.pool.telekom.hu/128 [::]                       Un   0   1     0 lo
fd4a:ca1:7e60:1:225:22ff:feec:4dae/128 [::]                       Un   0   1     0 lo
fd4a:ca1:7e60:1:960b:3982:8d00:77bf/128 [::]                       Un   0   1     0 lo
fe80::225:22ff:feec:4dae/128   [::]                       Un   0   3  3943 lo
ff00::/8                       [::]                       U    256 2  2371 enp3s0
[::]/0                         [::]                       !n   -1  1  9242 lo

Lone_Wolf · 2017-06-30 21:36:32

This doesn't make sense, the ipv6 /64 networks in that table appears twice with different metrics, but use the same interface for both metrics.

Your pc also seems to be connected to several /128 networks of your provider on a superfast connection with metric 0 .

No idea what went wrong, but I suggest to power cycle (just rebooting may not be enough) the router.

freyr · 2017-06-30 21:43:49

Lone_Wolf wrote:

This doesn't make sense, the ipv6 /64 networks in that table appears twice with different metrics, but use the same interface for both metrics.
Your pc also seems to be connected to several /128 networks of your provider on a superfast connection with metric 0 .
No idea what went wrong, but I suggest to power cycle (just rebooting may not be enough) the router.

Here's the output after the power cycle

Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
20014C4E13855B250000000000000000.dsl.pool.telekom.hu/64 [::]                       U    100 0     0 enp3s0
20014C4E13855B250000000000000000.dsl.pool.telekom.hu/64 [::]                       U    202 0     0 enp3s0
fd4a:ca1:7e60:1::/64           [::]                       U    100 0     0 enp3s0
fd4a:ca1:7e60:1::/64           [::]                       U    202 0     0 enp3s0
speedport.ip/128               [::]                       U    100 2    32 enp3s0
fe80::/64                      [::]                       U    256 0     0 enp3s0
[::]/0                         speedport.ip               UG   100 2     8 enp3s0
[::]/0                         [::]                       !n   -1  1    89 lo
localhost.localdomain/128      [::]                       Un   0   3    73 lo
20014C4E13855B25022522FFFEEC4DAE.dsl.pool.telekom.hu/128 [::]                       Un   0   3     5 lo
20014C4E13855B258D0797C317DA0D51.dsl.pool.telekom.hu/128 [::]                       Un   0   1     0 lo
fd4a:ca1:7e60:1:225:22ff:feec:4dae/128 [::]                       Un   0   1     0 lo
fd4a:ca1:7e60:1:960b:3982:8d00:77bf/128 [::]                       Un   0   1     0 lo
fe80::225:22ff:feec:4dae/128   [::]                       Un   0   3    87 lo
ff00::/8                       [::]                       U    256 2    31 enp3s0
[::]/0                         [::]                       !n   -1  1    94 lo

Of course it still doesn't work.

Last edited by freyr (2017-06-30 21:45:01)

freyr · 2017-07-01 06:45:41

Something's changed at night. My PC was off for some hours and now as I tried to connect to the webserver, FileZilla used the IPv4 address.
I opened a command line and checked the route -6 output which gave me this

Kernel IPv6 routing table
Destination                    Next Hop                   Flag Met Ref Use If
fe80::/64                      [::]                       U    256 2    40 enp3s0
[::]/0                         [::]                       !n   -1  1  1613 lo
localhost.localdomain/128      [::]                       Un   0   3    74 lo
fe80::225:22ff:feec:4dae/128   [::]                       Un   0   3    82 lo
ff00::/8                       [::]                       U    256 2    34 enp3s0
[::]/0                         [::]                       !n   -1  1  1613 lo

and the ping -6 google.com returned this

connect: Network is unreachable

I don't see any changes in the router though.

Lone_Wolf · 2017-07-01 12:03:19

Finally the routing table makes sense.
Your pc sees the local ipv6 network , but has no route for public ipv6 addresseses .

- what network configuration/management tools are you using

- try to get the ipv6 addresses of the router through the ipv4 interface.
It should have 2 addresses, one in your local fe80 network and another public one connecting it with your providers ipv6 network.

freyr · 2017-07-02 10:28:29

Thanks for the help but it seems the problem is on my ISP's side. I found a forum where many others talked about how IPv6 sometimes stops working recently for no reason.
Also, before I came here to write this, I pinged google.com with the -6 option and it works, I can also reach ipv6.google.com.

Sorry I bothered you.

Last edited by freyr (2017-07-02 10:35:14)

Lone_Wolf · 2017-07-02 20:32:39

No problem, it gave me a reason to refresh my knowledge about ipv6 routing tables.

Arch Linux

#1 2017-06-30 15:57:15

[Solved itself] Can't reach IPv6 addresses over the internet

#2 2017-06-30 18:30:27

Re: [Solved itself] Can't reach IPv6 addresses over the internet

#3 2017-06-30 20:41:20

Re: [Solved itself] Can't reach IPv6 addresses over the internet

#4 2017-06-30 21:36:32

Re: [Solved itself] Can't reach IPv6 addresses over the internet

#5 2017-06-30 21:43:49

Re: [Solved itself] Can't reach IPv6 addresses over the internet

#6 2017-07-01 06:45:41

Re: [Solved itself] Can't reach IPv6 addresses over the internet

#7 2017-07-01 12:03:19

Re: [Solved itself] Can't reach IPv6 addresses over the internet

#8 2017-07-02 10:28:29

Re: [Solved itself] Can't reach IPv6 addresses over the internet

#9 2017-07-02 20:32:39

Re: [Solved itself] Can't reach IPv6 addresses over the internet

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