ISC DHCPv6 bug?

[Mpegger]

I've come across a possible bug in DNS resolution of a local LAN FQDN address using ISC DHCPv6 static assignment.

My ISP issues dynamic IPv6 GUA prefixes in the /56 range. LAN is set to Tracking, RA is set to assisted, and I have Unbound setup as the main DNS server, and ISC handling DHCP for both v4 and v6 addresses, as well as passing both dynamic and static assignment DNS information to Unbound.

I normally have IPv6 addresses given out in a certain range (isp:isp:isp:isp::xxxx) via ISC DHCPv6, but am attempting to give out a Static IPv6 address to a single server for access outside my LAN. I configured this Static setting in ISC DHCPv6 by using the 'DUID Identifier', assigning a 'IPv6 address' in the form of (::1.2.3.4) since I have a dynamic IPv6 prefix, and used the same 'Hostname' for the client that I use in the DHCPv4 configuration. The client gets both the correct IPv4 and IPv6 addresses and I am able the forward traffic from the WAN side to the server in my network using its GUA IPv6 address that I assigned it.

The problem (bug?) comes when I try to access that server in my LAN using the FQDN (not IP). I noticed it would take some seconds (sometimes well over 30 seconds) before the server would respond when I tried to connect to it. Seeing as how I had made that ISC DHCPv6 entry just before the issue started happening I ran a simple 'ping server.lan.internal', and it was trying to ping the Static IPv6 portion of the address assigned to that server, *without* the ISP assigned prefix.

Code Select Expand

ping server.lan.internal

Pinging server.lan.internal [::1.2.3.4] with 32 bytes of data:
Running a nslookup resulted in the same portion of the IPv6 being reported without the ISP assigned GUA prefix.

Removing the 'Hostname' in the ISC DHCPv6 entry, restarting ISC DHCPv6 *and* Unbound services, did not clear the DNS responce. I had to reboot Opnsense in order to clear that responce. Once rebooted I was no longer getting any IPv6 address in nslookup, but this means that if I was trying to connect to the server on my LAN using only IPv6, I'd have to use the actual IP, and wouldn't be able to use a FQDN.

TL:DR -  It seems that ISC DHCPv6 is passing a incomplete IPv6 address to Unbound when using a dynamic IPv6 entry (::a.b.c.d) along with it's 'Hostname', and it won't clear without rebooting Unbound.