How can I troubleshoot when an IPV6 tunnel stops working?

by Tek   Last Updated September 11, 2019 22:02 PM

Assuming the configuration hasn't changed, how can I start troubleshooting? I woke up to not being able to ping IPv6 addresses.

Things to keep in mind:

  • IP Address didn't change. Public IP Address matches tunnelbroker.net
  • My configuration looks exactly like this
  • I can ping the tunnel endpoint 184.105.253.10
  • Didn't change firewall nor any configuration overnight
  • Using Ubuntu server 19.04

This is the relevant firewall rule I have up for this configuration:e

Chain ufw-user-input (1 references)
pkts bytes target     prot opt in     out     source           destination
8444 1302K ACCEPT     41   --  *      *       184.105.253.10       0.0.0.0/0

ip a

3: enp36s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:1b:21:c8:3c:f1 brd ff:ff:ff:ff:ff:ff
    inet6 fe80::21b:21ff:fec8:3cf1/64 scope link
       valid_lft forever preferred_lft forever
4: [email protected]: <NOARP> mtu 1480 qdisc noqueue state DOWN group default qlen 1000
    link/sit 0.0.0.0 brd 0.0.0.0
5: [email protected]: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1480 qdisc noqueue state UNKNOWN group default qlen 1000
    link/sit 192.168.0.1 peer 184.105.253.10
    inet6 2001:x:1f0e:x::2/64 scope global
       valid_lft forever preferred_lft forever
    inet6 fe80::c0a8:1/64 scope link
       valid_lft forever preferred_lft forever
6: [email protected]: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:1b:21:c8:3c:f1 brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.1/26 brd 192.168.0.63 scope global lan
       valid_lft forever preferred_lft forever
    inet6 2001:x:1f0f:x:21b:21ff:fec8:3cf1/64 scope global dynamic mngtmpaddr noprefixroute
       valid_lft 86337sec preferred_lft 14337sec
    inet6 fe80::21b:21ff:fec8:3cf1/64 scope link
       valid_lft forever preferred_lft forever
7: [email protected]: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 00:1b:21:c8:3c:f1 brd ff:ff:ff:ff:ff:ff
    inet 183.x.x.x/24 brd 47.187.53.255 scope global dynamic wan
       valid_lft 1459sec preferred_lft 1459sec
    inet6 fe80::21b:21ff:fec8:3cf1/64 scope link
       valid_lft forever preferred_lft forever

ip -6 route

::1 dev lo proto kernel metric 256 pref medium
2001:x:1f0e:x::/64 dev ipv6tunnel proto kernel metric 256 pref medium
2001:x:1f0f:x::/112 dev tun0 proto kernel metric 256 pref medium
2001:x:1f0f:x::/64 dev lan proto ra metric 1024 expires 86143sec pref medium
fe80::/64 dev ipv6tunnel proto kernel metric 256 pref medium
fe80::/64 dev enp36s0 proto kernel metric 256 pref medium
fe80::/64 dev wan proto kernel metric 256 pref medium
fe80::/64 dev lan proto kernel metric 256 pref medium
fe80::/64 dev tun0 proto kernel metric 256 pref medium
default via 2001:x:1f0e:x::1 dev ipv6tunnel proto static metric 1024 pref medium

netstat -rnf inet6

    Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         183.x.x.1     0.0.0.0         UG        0 0          0 wan
183.x.x.0     0.0.0.0         255.255.255.0   U         0 0          0 wan
183.x.x.1     0.0.0.0         255.255.255.255 UH        0 0          0 wan
192.168.0.0     0.0.0.0         255.255.255.192 U         0 0          0 lan

How can I start troubleshooting? Rebooting always fixes the problem but it's not an ideal solution because I have services on the router that need to have 100% uptime.



Related Questions


systemd resolve doesn't respond to queries

Updated May 10, 2018 16:02 PM

ipv6 tunnel in Ubuntu 17.10?

Updated December 28, 2017 11:02 AM



Netplan / systemd-networkd VLAN is missing

Updated July 24, 2018 14:02 PM