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General IPv6 Topics => IPv6 on Linux & BSD & Mac => Topic started by: Nomadadon on May 07, 2020, 12:28:24 PM

Title: Ubuntu 19.10 and 20.04 tunnel stops passing IPv6 traffic only
Post by: Nomadadon on May 07, 2020, 12:28:24 PM

I've had my tunnel up for a good while, but sometime in the last few months, I don't know when it started happening, but after my firewall as been up for a week, give or take 3 days, it's random, it will just stop passing traffic.

Interface is up, routes are up, I can ping the remote IPv4 and the local IPv6, but 100% packet loss over the IPv6.  No changes to the firewall rules ( iptables ) or any config, it just starts dropping all packets.  As if I'm blocking a keepalive protocol I can't find docs on.  If I reboot my linux box, traffic resumes without issue.  If I down the interface and restart IPTables, no go, still dead.
 
Here's my config:

iface he-ipv6 inet6 v4tunnel
    # Bring up the actual tunnel
    address 2001:470:39:57c::2
    netmask 64
    endpoint 184.105.250.46
    #local `/usr/local/bin/GetExternalIP.sh`
    local 209.182.74.168
    ttl 255
    gateway 2001:470:39:57c::1
    post-up /etc/init.d/Firewall-6.sh restart
    #
    # For shutting down the interface
    down /sbin/ip route del ::/0 dev he-ipv6 2>/dev/null
    down /sbin/ifconfig he-ipv6 down 2>/dev/null
    down /sbin/ip link set he-ipv6 down 2>/dev/null
    post-down /sbin/ifconfig sit0 0.0.0.0 2>/dev/null
    post-down /sbin/ifconfig sit0 down 2>/dev/null
    post-down /sbin/ifconfig sit1 0.0.0.0 2>/dev/null
    post-down /sbin/ifconfig sit1 down 2>/dev/null
    post-down /sbin/modprobe -r sit 2>/dev/null

07:42:/home/nomad>ifconfig he-ipv6
he-ipv6: flags=209<UP,POINTOPOINT,RUNNING,NOARP>  mtu 1480
        inet6 fe80::d1b5:4da8  prefixlen 64  scopeid 0x20<link>
        inet6 2001:470:39:57c::2  prefixlen 64  scopeid 0x0<global>
        sit  txqueuelen 1000  (IPv6-in-IPv4)
        RX packets 2504594  bytes 2856452096 (2.8 GB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1470748  bytes 248227701 (248.2 MB)
        TX errors 542  dropped 0 overruns 0  carrier 536  collisions 0

07:44:/home/nomad>ip -6 route
::1 dev lo proto kernel metric 256 pref medium
2001:470:39:57c::1 dev he-ipv6 metric 1024 pref medium
2001:470:39:57c::/64 dev he-ipv6 proto kernel metric 256 pref medium
2001:470:4b:57c::/64 dev em1 proto kernel metric 256 pref medium
fe80::/64 dev he-ipv6 proto kernel metric 256 pref medium
fe80::/64 dev enp9s4 proto kernel metric 256 pref medium
fe80::/64 dev em1 proto kernel metric 256 pref medium
fe80::/64 dev em1.5 proto kernel metric 256 pref medium
fe80::/64 dev em1.10 proto kernel metric 256 pref medium
fe80::/64 dev em1.99 proto kernel metric 256 pref medium
fe80::/64 dev em1.101 proto kernel metric 256 pref medium
default via 2001:470:39:57c::1 dev he-ipv6 metric 1024 onlink pref medium


07:42:/home/nomad>ping -c 3 184.105.250.46
PING 184.105.250.46 (184.105.250.46) 56(84) bytes of data.
64 bytes from 184.105.250.46: icmp_seq=1 ttl=59 time=8.85 ms
64 bytes from 184.105.250.46: icmp_seq=2 ttl=59 time=8.55 ms
64 bytes from 184.105.250.46: icmp_seq=3 ttl=59 time=8.60 ms

--- 184.105.250.46 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2004ms
rtt min/avg/max/mdev = 8.553/8.668/8.854/0.132 ms

07:42:/home/nomad>ping -c 3 2001:470:39:57c::2
PING 2001:470:39:57c::2(2001:470:39:57c::2) 56 data bytes
64 bytes from 2001:470:39:57c::2: icmp_seq=1 ttl=64 time=0.070 ms
64 bytes from 2001:470:39:57c::2: icmp_seq=2 ttl=64 time=0.051 ms
64 bytes from 2001:470:39:57c::2: icmp_seq=3 ttl=64 time=0.059 ms

--- 2001:470:39:57c::2 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2035ms
rtt min/avg/max/mdev = 0.051/0.060/0.070/0.007 ms

07:42:/home/nomad>ping -c 3 2001:470:39:57c::1
PING 2001:470:39:57c::1(2001:470:39:57c::1) 56 data bytes

--- 2001:470:39:57c::1 ping statistics ---
3 packets transmitted, 0 received, 100% packet loss, time 2041ms

Title: Re: Ubuntu 19.10 and 20.04 tunnel stops passing IPv6 traffic only
Post by: cholzhauer on May 08, 2020, 05:59:03 AM
It does sound as if keep-alive is being blocked somehow.  I haven't seen a post of this type on here in a few years, but the solution then was just to create a cron job to run ping every so often. 
Title: Re: Ubuntu 19.10 and 20.04 tunnel stops passing IPv6 traffic only
Post by: Nomadadon on May 08, 2020, 10:46:28 AM
I've got traffic flowing across it almost constantly though.