OpenWrt/LEDE Project

  • Status Unconfirmed
  • Percent Complete
  • Task Type Bug Report
  • Category Base system
  • Assigned To No-one
  • Operating System All
  • Severity High
  • Priority Very Low
  • Reported Version Trunk
  • Due in Version Undecided
  • Due Date Undecided
  • Private
Attached to Project: OpenWrt/LEDE Project
Opened by Mario Enrico Ragucci - 13.09.2018

FS#1844 - R7800 ipv6 connectivity


ipv6 does not work properly on my Netgear R7800. I am running OpenWrt 18.6.1. The device gets a ipv6 address assigned, but I cannot ping any ipv6 address. Furthermore, I get the following error:
# ping6
PING (2607:f8b0:4000:817::2003): 56 data bytes
ping6: sendto: Permission denied

After running the command
# tcpdump -i eth0 -vv
for some time, ipv6 connectivity works, I am able to ping an ipv6 address, also pinging from another host and establishing v6 connections is working.
# ping6
PING (2607:f8b0:4000:817::2003): 56 data bytes
64 bytes from 2607:f8b0:4000:817::2003: seq=0 ttl=51 time=118.360 ms
64 bytes from 2607:f8b0:4000:817::2003: seq=1 ttl=51 time=118.626 ms

However, after some time, this is not working anymore and I have to restart the tcpdump command.

This must be a device specific issue, since my other Netgear Router (WNDR3700) running 18.06.1 is working flawlessly.

Hannu Nyman commented on 14.09.2018 21:42

To my knowledge there is no device-specific IPv6 problem with R7800.
IPv6 has worked quite ok for me with 17.01, 18.06 and master.

root@router1:~# grep r /etc/banner
 OpenWrt SNAPSHOT, r8059-8cac857289

root@router1:~# cat /tmp/sysinfo/model
Netgear Nighthawk X4S R7800

root@router1:~# ping6
PING (2a00:1450:400f:806::2003): 56 data bytes
64 bytes from 2a00:1450:400f:806::2003: seq=0 ttl=53 time=15.747 ms
64 bytes from 2a00:1450:400f:806::2003: seq=1 ttl=53 time=15.580 ms
64 bytes from 2a00:1450:400f:806::2003: seq=2 ttl=53 time=15.587 ms
--- ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 15.580/15.638/15.747 ms
lbdroid commented on 03.12.2018 18:40

I'm getting the same behavior with a TP-Link Archer C2600.
Note: The netgear is an IPQ8065, the TP-Link is an IPQ8064. Same CPU, just clocked differently. IPv6 upstream shows "not connected" on the status overview page, but continues to show connected on the network interfaces page. If I hit the "restart" button on network interfaces –> WAN6, it will fix it.

Jon Doh commented on 08.09.2019 10:23

@Hannu Nyman: First, I don't think this is a proper bug report, you didn't provide any info on your setup. You should ask things like these in the forums and see if someone can solve your issue, or if the conversation reveals it to really be a bug.

Nonetheless maybe you're having the same issue as me. In my case there is an upstream router from my ISP providing IPV6 addresses, and my OpenWRT box was always loosing ipv6 connectivity after a certain time. Like in your case, when running tcpdump everything would work, then after shutting down tcpdump the connection would drop again after a while.
In my case the workaround for this was to issue "ifconfig <interface> allmulti" in a shell on the router, for the interface connected to the upstream ISP router. You should be able to get the interface name by looking at your LUCI overview page. I don't know if this is the ideal solution, but it works for me.
Once you have checked the command is working, you can add it to your rc.local accessible in LUCI System/Startup.
In my case I had to put a "sleep 60" before the "ifconfig", because the interface was not up yet when rc.local is run.


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