radvd - Too many addresses in RDNSS section when previously using DHCPv6
I have come across a bug within the IPv6 Router Advertising Daemon where you receive the following errors in the logs:
Oct 23 20:40:59 radvd 17699 version 1.9.1 started
Oct 23 20:40:59 radvd 17699 Too many addresses in RDNSS section
Oct 23 20:40:59 radvd 17699 error parsing or activating the config file: /var/etc/radvd.conf
Oct 23 20:40:59 radvd 17699 Exiting, failed to read config file.
However there were no DNSv6 servers configured in General Settings nor in RADVD itself as Server 2012 R2 DHCPv6 was handling this. Having browsed /var/etc/radvd.conf I found there were some stale DNSv6 addresses from a previous ISP in there. So I cleared the file and restarted RADVD. However DNSv6 addresses returned.
I then examined /cf/conf/config.xml
I did a search for one of the stale DNSv6 entries and I found that where this PFsense had previously been acting as a DHCPv6 server that it had kept the old settings in the <dhcpv6></dhcpv6> despite being disabled. Deleting the entire <dhcpv6></dhcpv6> section in this file, saving and restarting RADVD did resolve the problem.
Seems like that evena after you disable dhcpv6 in PFsense it keeps the settings in the config.xml file. Should this be looked at and potentially omitted somehow if marked as disabled so this does not break RADVD at a later point?