IPv6 Not Working on Openwrt on Netgear R6220 with Load Balancing

trendy · May 17, 2021, 9:30am

Let's have a look how it all looks like now.
Please run the following commands (copy-paste the whole block) and paste the output here, using the "Preformatted text </> " button:

Remember to redact passwords, MAC addresses and any public IP addresses you may have

ubus call system board; \
uci export network; uci export mwan3; \
uci export dhcp; uci export firewall; \
head -n -0 /etc/firewall.user; \
ip6tables-save -c; \
ip -6 addr ; ip -6 ro li tab all ; ip -6 ru; \
ls -l  /etc/resolv.* /tmp/resolv.* /tmp/resolv.*/* ; head -n -0 /etc/resolv.* /tmp/resolv.* /tmp/resolv.*/*

Audioctor · May 20, 2021, 3:01am

Thanks. @vgaetera and @trendy . The whole block was exceeding the character limit. so, I pasted it in pastebin. I have shared it here.

trendy · May 20, 2021, 10:32am

config zone
        option name 'wan'
...
        option masq6 ''\''1'\'''

Is this correct or a typo?
Other than that, there is a gateway conflict between eth0.3 and eth0.4, so you have the gateway of eth0.4 only installed on the main routing table. Apart from that, I don't see any issue. Try to do a traceroute6 from a lan host to the google.com to verify that it works.

Audioctor · May 21, 2021, 3:49am

It cannot be a typo. I copy-pasted it as it is.
Here's traceroute4 from PC

C:\Users\harsh>tracert google.com

Tracing route to google.com [142.250.194.174]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  192.168.2.1
  2    <1 ms    <1 ms    <1 ms  OpenWrt.lan [192.168.0.1]
  3     1 ms    <1 ms    <1 ms  192.168.29.1
  4     5 ms     2 ms     4 ms  10.22.72.1
  5     8 ms     6 ms     7 ms  172.31.0.126
  6     6 ms     7 ms     7 ms  192.168.65.94
  7     6 ms     7 ms     7 ms  172.26.74.165
  8     7 ms     6 ms     6 ms  172.26.74.146
  9    16 ms    16 ms    21 ms  192.168.65.80
 10    11 ms    20 ms    15 ms  192.168.65.81
 11    19 ms    19 ms    20 ms  172.31.2.71
 12    22 ms    19 ms    21 ms  74.125.51.166
 13    21 ms    22 ms    20 ms  209.85.247.207
 14    20 ms    22 ms    22 ms  108.170.248.202
 15    30 ms    29 ms    21 ms  172.253.68.121
 16    50 ms    47 ms    47 ms  72.14.232.139
 17    43 ms    42 ms    43 ms  108.170.251.113
 18    41 ms    42 ms    42 ms  142.251.52.221
 19    44 ms    44 ms    46 ms  del12s06-in-f14.1e100.net [142.250.194.174]

Trace complete.

Here's traceroute6 from same PC:

C:\Users\harsh>tracert -6 google.com

Tracing route to google.com [2404:6800:4009:80b::200e]
over a maximum of 30 hops:

  1     *        *        *     Request timed out.
  2     *        *        *     Request timed out.
  3     *        *        *     Request timed out.
  4     *        *        *     Request timed out.
  5     *        *        *     Request timed out.
  6     *        *        *     Request timed out.
  7     *        *        *     Request timed out.
  8     *        *        *     Request timed out.
  9     *        *        *     Request timed out.
 10     *        *        *     Request timed out.
 11     *        *        *     Request timed out.
 12     *        *        *     Request timed out.
 13     *        *        *     Request timed out.
 14     *        *        *     Request timed out.
 15     *        *        *     Request timed out.
 16     *        *        *     Request timed out.
 17     *        *        *     Request timed out.
 18     *        *        *     Request timed out.

And here's traceroute6 from my Openwrt router:

traceroute to google.com (2404:6800:4002:823::200e), 30 hops max, 64 byte packets
 1  2405:201:300f:d4::c0a8:1d01  0.896 ms
 2  *
 3  2405:203:400:100:172:31:0:126  7.915 ms
 4  2001:4860:1:1::3c9  24.941 ms
 5  2001:4860:1:1::3c8  26.445 ms
 6  *
 7  2001:4860::9:4001:d9e7  42.130 ms
 8  2001:4860:0:115b::2  25.750 ms
 9  2001:4860:0:1::53a1  42.012 ms
10  2404:6800:4002:823::200e  39.957 ms

Lastly, the Internet connection running on eth0.3 does not have an IPv6 provided by the ISP yet. Wonder if that could be the reason that its gateway is not installed on the main routing table.

trendy · May 21, 2021, 8:36am

I see an extra hop here. Connect the PC directly on the OpenWrt and try again.

That explains it.
Also remove the mtu 1492 from wanc6.

Audioctor · May 22, 2021, 12:47am

That extra hop was due to my Main Router and DHCP Server for my Network which is placed downstream from the OpenWrt.

Here's the Traceroute4 from PC (directly connected to OpenWrt):

C:\Users\harsh>tracert google.com

Tracing route to google.com [142.250.194.238]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  OpenWrt.lan [192.168.0.1]
  2    <1 ms    <1 ms    <1 ms  192.168.29.1
  3     2 ms     1 ms     1 ms  10.22.72.1
  4     7 ms     8 ms     6 ms  172.31.0.126
  5     7 ms     5 ms     6 ms  192.168.65.90
  6     6 ms     6 ms     6 ms  172.26.74.165
  7     8 ms     6 ms     8 ms  172.26.74.146
  8     6 ms     6 ms     5 ms  192.168.65.78
  9     7 ms     8 ms     6 ms  192.168.65.79
 10    18 ms    19 ms    19 ms  172.31.2.71
 11    20 ms    28 ms    26 ms  209.85.168.26
 12    19 ms    19 ms    19 ms  209.85.247.65
 13    20 ms    19 ms    19 ms  108.170.248.203
 14    20 ms    21 ms    19 ms  216.239.54.93
 15    41 ms    47 ms    41 ms  142.250.234.127
 16    43 ms    43 ms    43 ms  108.170.251.97
 17    41 ms    41 ms    41 ms  142.251.52.215
 18    40 ms    41 ms    41 ms  del12s08-in-f14.1e100.net [142.250.194.238]

Trace complete.

Now here's Traceroute6from the same PC:

C:\Users\harsh>tracert -6 google.com

Tracing route to google.com [2404:6800:4002:804::200e]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  2001:4490:4409:8151:5ad5:6eff:fe6d:ba8e
  2     *        *        *     Request timed out.
  3     *        *        *     Request timed out.
  4     *        *        *     Request timed out.
  5     *        *        *     Request timed out.
  6     *        *        *     Request timed out.
  7     *        *        *     Request timed out.
  8     *        *        *     Request timed out.
  9     *        *        *     Request timed out.
 10     *        *        *     Request timed out.
 11     *        *        *     Request timed out.
 12     *        *        *     Request timed out.
 13     *        *        *     Request timed out.
 14     *        *        *     Request timed out.
 15     *        *        *     Request timed out.
 16     *        *        *     Request timed out.
 17     *        *        *     Request timed out.
 18

And this is traceroute6 directly from OpenWrt:

traceroute to google.com (2404:6800:4009:80e::200e), 30 hops max, 64 byte packets
 1  2405:201:300f:d4::c0a8:1d01  0.981 ms
 2  *
 3  2405:203:400:100:172:31:0:126  9.874 ms
 4  2405:200:802:760::8  26.942 ms
 5  *
 6  2001:4860:1:1::1022  24.927 ms
 7  2404:6800:80b3::1  27.249 ms
 8  2001:4860:0:115c::1  30.496 ms
 9  *
10  2404:6800:4009:80e::200e  29.401 ms

I had removed the MTU 1492 from wanc6 before this operation.

trendy · May 22, 2021, 6:52pm

to whom does this prefix belong to? I was not able to find it in the available prefixes in your previous post.

Audioctor · May 27, 2021, 5:26am

You are right. It was not there when I was connected through my main router and did my first test. But it came during my second test when I was connected directly to Openwrt. Its coming from wanc6.

But strangely, its not coming now , even though I am connected directly to Openwrt.

C:\Users\harsh>tracert -6 google.com

Tracing route to google.com [2404:6800:4009:829::200e]
over a maximum of 30 hops:

  1     *        *        *     Request timed out.
  2     *        *        *     Request timed out.
  3     *        *        *     Request timed out.
  4     *        *        *     Request timed out.
  5     *        *        *     Request timed out.
  6     *        *        *     Request timed out.
  7     *        *        *     Request timed out.
  8     *        *        *     Request timed out.
  9     *        *        *     Request timed out.
 10     *        *        *     Request timed out.
 11     *        *        *     Request timed out.
 12     *        *        *     Request timed out.
 13     *        *        *     Request timed out.
 14     *        *        *     Request timed out.
 15     *        *        *     Request timed out.
 16     *        *        *     Request timed out.
 17     *        *        *     Request timed out.
 18     *        *        *     Request timed out.
 19     *        *        *     Request timed out.
 20     *        *        *     Request timed out.
 21     *        *        *     Request timed out.
 22     *        *        *     Request timed out.
 23     *        *        *     Request timed out.
 24     *        *        *     Request timed out.
 25     *        *        *     Request timed out.
 26     *        *        *     Request timed out.
 27     *        *        *     Request timed out.
 28     *        *        *     Request timed out.
 29     *        *        *     Request timed out.
 30     *        *        *     Request timed out.

Trace complete.

The difference is, previously I was connected to Openwrt through LAN (when I got that Prefix ) while right now I am connected through WLAN.

trendy · May 27, 2021, 8:03am

Wifi is bridged with lan, right? Then it doesn't make any difference where you are connected.

Audioctor · May 28, 2021, 3:49pm

Yes its bridged.
Here's the configuration screenshot:

trendy · May 28, 2021, 10:06pm

The only reason I can think of is that the wifi doesn't have ipv6 enabled. Otherwise the OpenWrt doesn't differentiate the wireless from the wired since they are bridged.

Audioctor · June 1, 2021, 3:43am

Hello all. Its working now.

I toggled with certain settings on my Openwrt.
I disabled Inbuilt IPv6 management in all the WAN interfaces while I kept it enabled on LAN interface.

I kept the LAN DHCP IPv6 settings in "server-mode" with NDP-proxy disabled and DHCPv6-mode "stateless+stateful".

In the firewall Traffic Rule settings I enabled Allow-DHCP renew, Allow-Ping and Allow-IGMP for both IPv4 and IPv6.

That's it.
Thanks to you all guys.

trendy · June 1, 2021, 10:21am

The first is wrong, DHCPv6 works on a different port than DHCPv4. The 4th rule allows the DHCPv6.
The second rule is for IPv4 Ping. For IPv6 there are rules #6 and #7. Having disabled rule #7 you are blocking traffic which is important to reach the internal hosts, like packet-too-big icmp.

Audioctor · June 2, 2021, 5:17am

Thanks. I made the changes.

It still works.

system · June 12, 2021, 5:18am

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