For my home LAN I use an ASUS RT-N66U running the Asuswrt-Merlin (374.43 LTS) fork which is a nice simple and stable firmware and also updated regularly. My ISP is BT in the UK.

I have been using only IPv4 but decided to switch on IPv6, which BT supports.

The settings that work seem to be straightforward and mostly default:

Connection Type: Native
Interface: PPP
DHCP-PD: enable
MTU: 1492

LAN Options:

Auto Configuration: Stateless
LAN Prefix Length: 64

Enable Router Advertisement: Enable
Enable DHCPv6 Server: Disable

I also used these "Special ISP Options" (the first two are default while the third is not):

Enable IPv6 MTU advertisement: Yes
Release addresses on exit: Yes
Prefix delegation requires address request​: Yes

The issue seems to arise with this last setting.

If I set it to Yes, then I get IPv6 working but my log fills up with these messages - about 1 a second:

dhcp6c: dhcp6c state change detected SOLICIT​

Apart from the log messages, everything else seems to be working. My router doesn't get a global WAN IPv6 address but apparently BT don't provide one anyway. I think maybe that is the cause of the message: my router is requesting a WAN side global address and not getting one.

However, it seems that I do need this setting to get a prefix from BT. If I change the setting to No then the log messages stop but I also lose the IPv6 Gateway and the delegated prefix and, of course, IPv6 stops working.

I can't seem to get IPv6 working without the log filling up (and presumably wasted Solicit messages going out every second).

Any suggestions for what's going on and how to proceed?

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