System log shows IPv6 addresses

Installing and Using OpenWrt
1

Hello,
OpenWrt seems to show IPV6 addresses for devices on my local LAN in the logs. Since I only assign static IPV4 addresses I don't know what devices the addresses refer to and I don't know where I could check which device they belong to.

Fri Feb  2 12:44:00 2024 daemon.info dnsmasq[1]: 880 fe80::7007:49ff:feb4:cae9%eth0/53180 query[A] www.google.com from fe80::7007:49ff:feb4:cae9
Fri Feb  2 12:44:00 2024 daemon.info dnsmasq[1]: 880 fe80::7007:49ff:feb4:cae9%eth0/53180 cached www.google.com is 142.250.187.196
Fri Feb  2 12:45:00 2024 daemon.info dnsmasq[1]: 881 fe80::7007:49ff:feb4:cae9%eth0/52097 query[A] www.google.com from fe80::7007:49ff:feb4:cae9
Fri Feb  2 12:45:00 2024 daemon.info dnsmasq[1]: 881 fe80::7007:49ff:feb4:cae9%eth0/52097 cached www.google.com is 142.250.187.196

Any advice would be much appreciated.
Thank you.

2

Normally the router will advertise its ULA address to the lan hosts to use for DNS, but maybe you disabled it so it is now advertising the LL address.
What is the output of:

Please run the following commands (copy-paste the whole block) and paste the output here, using the "Preformatted text </> " button:
grafik
Remember to redact passwords, MAC addresses and any public IP addresses you may have

ubus call system board; \
uci export network; \
uci export dhcp; uci export firewall; \
ip -6 addr ; ip -6 ro li tab all ; ip -6 ru
3

ip -6 neigh

You can also see this information on the web GUI under Routing > IPv6 Routing > IPv6 Neighbors.

4

That is normal and not harmful-- some clients are using V6 link-local to access the DNS server on the router. They then use the "A" result which is IPv4 to access the site on the Internet.

The ff:fe in the middle of the address means that this particular LLA was derived from the device's MAC address using the EUI64 standard method. The other bits except for one are the MAC address of the device that sent it.

Setting option ipv6 0 on LAN will prevent the LAN interface from having a link-local IP, thus clients must strictly use IPv4.

1 Like
5

First, you can’t turn of IPv6, it is nowadays hardcoded in kernel.

fe80 is link local address and actually means that the device in question have no assign and routable ipv6 address.

It is the same as the old ipv4 address 169.254.0.0/16.

Does it start with 2001, then you have an internet connected address.

Locally dhcp assign ipv6 addresses usually start with fd.

6

Thanks everybody for providing useful information.
Adding the above options to /etc/config/network in the LAN interface section seems to have done the trick.

7

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