I have built a Linux based router for a network testing environment. The machine has 4 physical ethernet ports
All 3 lan* interfaces are bridged on my lan device. I am running dnsmasq to provide DHCP/DNS on the lan interface. I am trying to use SLAAC IPv6 addresses instead of DHCPv6 assigned addresses and am using DHCPv6 for other information (so stateless DHCPv6). All other computers on my lan correctly assign themselves addresses via SLAAC. However even though dnsmasq is sending router advertisements on the lan interface my wan interface is somehow seeing it and autoconfiguring itself. I have run wireshark on my wan interface and there are no incoming router advertisements actually coming over the network.
I have even tried turning off slaac on my wan interface by setting the net.ipv6.conf.wan.autoconf key to 0 via sysctl but it still gets an address.
Is there any other way that this could be happening.