I have been a long-time pfSense user and just migrated my home setup to OPNsense 25.7-amd64. A while back I had stopped using the pfSense DHCP and DNS servers and set up Technitium (https://technitium.com/dns/) on my network, so I had no plans to use any of the DNS or DHCP features in OPNsense. I set up OPNsense and everything seemed to be going well until I tried to do DNS lookups of my LAN systems from my LAN, and they didn't look up. I checked a client DHCP lease and it had an IPv6 entry for a DNS server which I had never seen in my pfSense setup (see attached). When the OPNsense setup asked about configuring a DHCP or DNS server I had said no, and when I set up Technitium everything in that is IPv4, so this is very perplexing.
I went through all the OPNsense DHCP and DNS server settings, and I did find that that ISC DHCPv6 was set to "Enable DHCPv6 on LAN interface", which I had not configured during setup and don't remember it asking to enable that at any point. So I unchecked it, hit save, and then renewed a client DHCP lease. No change. So then I went to the LAN interface configuration in OPNsense, and tried to change the IPv6 Configuration type from "Track Interface" to "None", but that throws this error:
QuoteThe following input errors were detected:
The DHCPv6 Server is active on this interface and it can be used only with a static IPv6 configuration. Please disable the DHCPv6 Server service on this interface first, then change the interface configuration.
I have verified that there is no DHCPv6 Server service active on this interface in the GUI, so now I am very confused. I went through all the settings, double-checked, and rebooted OPNsense, but I can't change the LAN IPv6 Configuration Type to "None", same error every time. For now I have resorted to changing the WAN IPv6 Configuration Type to "None", which finally cleared the IPv6 DNS server from my clients.
Even with the WAN IPv6 Configuration Type to "None", and no DHCPv6 server enabled anywhere in the GUI, I still cannot get the LAN IPv6 Configuration Type moved off of "Track Interface".
Are these bugs in OPNsense? What is the proper way to get things set up?
Hi,
I have exactly the same problem
My computers have opnsense as prefered dns 😕
QuoteServeurs DNS. . . . . . . . . . . . . : 2001:861:4080:bff3:215:5dff:fe96:a36
192.168.100.1
8.8.8.8
So, no resolution of my lan server.
my lan have a dns and a dhcp server configured juste with ipv4 (active directory domain)
All dhcp and dns are disable on my opnsense
I desactived ISC DHCPv6 lan and all work fine
What is the best way for me to gather information regarding the true state of the DHCPv6 server so I can file a bug report?
I think either DHCPv6 and/or IPv6 RAs are advertising the DNS server to your clients.
Do you intend to use IPv6?
If no, then disable IPv6 from all your interfaces. Start with the LAN-side interfaces and disable it on WAN last.
Also go trough all of the available DHCP services in OPNsense (ISC, Dnsmasq, Kea) and make sure that DHCPv6 is not active on any of them and that no IPv6 ranges are defined in Dnsmasq. Also disable the RA services from Dnsmasq (General->DHCP->Router Advertisements) and make sure that the default Router Advertisement service (outside of Dnsmasq, under Services->Router Advertisements) is not enabled. If you don't see the Router Advertisements service listed in the menu that means it's not being used. There's also an "Allow IPv6" setting under Interfaces->Settings, but I don't think that's needed and should probably stay checked except for special circumstances.
In case the IPv6 configuration is coming via RAs then DHCP release/renew will not clear it. You'll need to reset your host's network connection.
If yes, then check out @meyergru's guide: https://forum.opnsense.org/index.php?topic=45822.0
You can specify your own DNS server in the IPv6 RAs using RDNSS in this case.
Quote from: OPNenthu on July 29, 2025, 02:29:16 AMI think either DHCPv6 and/or IPv6 RAs are advertising the DNS server to your clients.
Do you intend to use IPv6?
If no, then disable IPv6 from all your interfaces. Start with the LAN-side interfaces and disable it on WAN last.
Also go trough all of the available DHCP services in OPNsense (ISC, Dnsmasq, Kea) and make sure that DHCPv6 is not active on any of them and that no IPv6 ranges are defined in Dnsmasq. Also disable the RA services from Dnsmasq (General->DHCP->Router Advertisements) and make sure that the default Router Advertisement service (outside of Dnsmasq, under Services->Router Advertisements) is not enabled. If you don't see the Router Advertisements service listed in the menu that means it's not being used. There's also an "Allow IPv6" setting under Interfaces->Settings, but I don't think that's needed and should probably stay checked except for special circumstances.
In case the IPv6 configuration is coming via RAs then DHCP release/renew will not clear it. You'll need to reset your host's network connection.
If yes, then check out @meyergru's guide: https://forum.opnsense.org/index.php?topic=45822.0
You can specify your own DNS server in the IPv6 RAs using RDNSS in this case.
I don't intend to use IPv6 unless there is a good reason to (is there one?)
Like I said in my post, I haven't been able to disable IPv6 on the LAN side because no matter what, it says I have a DHCPv6 Server active, even though it is not enabled in the GUI. All DHCP services are off - ISC, Dnsmasq, and Kea. Services > Router Advertisements > [LAN] was set to "Assisted" and I just changed it to "Disabled". Interfaces > Settings does show "Allow IPv6" as checked and I've left it alone as you recommended.
Right now if I try to change my [LAN] interface IPv6 Configuration Type from "Track Interface" to "None" I still get "The DHCPv6 Server is active on this interface and it can be used only with a static IPv6 configuration. Please disable the DHCPv6 Server service on this interface first, then change the interface configuration." My [WAN] IPv6 Configuration Type is set to "None". Like I mentioned in my post, since I did that, client release/renew of DHCP cleared the DHCPv6 DNS server entry, which restored name lookups on my LAN via my Technitium server at least.
So back to my question - is there anything I can do via the command line to determine whether the DHCPv6 Server is still active despite it being disabled everywhere in the GUI? I'd just like to make an accurate bug report, and I need to know whether the DHCPv6 Server is still active and the GUI isn't accurately reflecting the state, or whether the DHCPv6 Server is inactive and the part of the GUI that determines whether it is active is broken. It is one of those two things, and it is preventing me from changing the IPv6 Configuration Type for my LAN.
Quote from: nray on Today at 03:27:52 AMs there anything I can do via the command line to determine whether the DHCPv6 Server is still active
'ps aux' to list all the processes and 'sockstat -l' to see what's listening.
Quote from: OPNenthu on Today at 04:39:17 AMQuote from: nray on Today at 03:27:52 AMs there anything I can do via the command line to determine whether the DHCPv6 Server is still active
'ps aux' to list all the processes and 'sockstat -l' to see what's listening.
USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND
root 11 600.0 0.0 0 96 - RNL Sun11 30966:29.09 [idle]
root 0 0.0 0.0 0 896 - DLs Sun11 16:29.96 [kernel]
root 1 0.0 0.0 12324 996 - ILs Sun11 0:00.06 /sbin/init
root 2 0.0 0.0 0 96 - WL Sun11 1:02.24 [clock]
root 3 0.0 0.0 0 112 - DL Sun11 0:00.00 [crypto]
root 4 0.0 0.0 0 64 - DL Sun11 0:00.07 [cam]
root 5 0.0 0.0 0 16 - DL Sun11 0:00.00 [busdma]
root 6 0.0 0.0 0 16 - DL Sun11 2:13.48 [pf purge]
root 7 0.0 0.0 0 16 - DL Sun11 0:34.82 [rand_harvestq]
root 8 0.0 0.0 0 16 - DL Sun11 0:00.30 [enc_daemon0]
root 9 0.0 0.0 0 48 - DL Sun11 0:13.84 [pagedaemon]
root 10 0.0 0.0 0 16 - DL Sun11 0:00.00 [audit]
root 12 0.0 0.0 0 288 - WL Sun11 0:15.92 [intr]
root 13 0.0 0.0 0 48 - DL Sun11 0:00.00 [geom]
root 14 0.0 0.0 0 16 - DL Sun11 0:00.00 [sequencer 00]
root 15 0.0 0.0 0 80 - DL Sun11 0:10.22 [usb]
root 16 0.0 0.0 0 16 - DL Sun11 0:03.94 [acpi_thermal]
root 17 0.0 0.0 0 16 - DL Sun11 0:00.00 [vmdaemon]
root 18 0.0 0.0 0 144 - DL Sun11 0:13.16 [bufdaemon]
root 19 0.0 0.0 0 16 - DL Sun11 0:01.36 [vnlru]
root 20 0.0 0.0 0 16 - DL Sun11 1:18.91 [syncer]
root 385 0.0 0.0 28108 14744 - Is Sun11 0:00.82 /usr/local/bin/python3 /usr/local/opnsense/service/configd.py (python3.11)
root 387 0.0 0.1 92444 39788 - I Sun11 0:08.80 /usr/local/bin/python3 /usr/local/opnsense/service/configd.py console (python3.11)
root 1061 0.0 0.0 15340 4036 - Is Sun11 0:00.17 /sbin/devd
root 1069 0.0 0.0 14028 2332 - Is Sun11 0:00.00 /usr/sbin/moused -p /dev/ums0 -t auto -I /var/run/moused.ums0.pid
root 5931 0.0 0.0 14076 2584 - Is Tue07 0:00.02 dhclient: system.syslog (dhclient)
root 9766 0.0 0.0 14312 2608 - I 22:00 0:00.00 /bin/sh /usr/local/opnsense/scripts/firmware/launcher.sh -u changelog cron
root 10149 0.0 0.0 14076 2648 - Is Tue07 0:00.07 dhclient: ix0 [priv] (dhclient)
root 11319 0.0 0.0 14312 2616 - I 22:00 0:00.00 /bin/sh /usr/local/opnsense/scripts/firmware/changelog.sh cron
root 11527 0.0 0.0 27368 14196 - S Sun11 0:23.17 /usr/local/bin/python3 /usr/local/sbin/configctl -e -t 0.5 system event config_changed (python3.11)
root 15867 0.0 0.1 64304 34604 - I Sun11 0:01.09 /usr/local/bin/php-cgi
root 16464 0.0 0.0 13924 2432 - SCs Sun11 1:15.06 /usr/sbin/rtsold -aiu -p /var/run/rtsold.pid -A /var/etc/rtsold_script.sh -R /usr/local/opnsense/scripts/interfaces/rtsold_resolvconf.sh
root 17259 0.0 0.1 59804 31356 - I 20:40 0:00.13 /usr/local/bin/php-cgi
root 17856 0.0 0.0 13924 2400 - Is Sun11 0:00.00 rtsold: rtsold.llflags (rtsold)
root 18092 0.0 0.0 13924 2404 - Is Sun11 0:00.00 rtsold: rtsold.script (rtsold)
root 18292 0.0 0.0 13852 2552 - Is Sun11 0:03.28 /usr/sbin/cron -s
root 18866 0.0 0.0 13648 2072 - IC 22:00 0:00.00 sleep 26825
root 18979 0.0 0.0 13924 2396 - Is Sun11 0:00.00 rtsold: rtsold.sendmsg (rtsold)
root 19113 0.0 0.0 13924 2408 - Ss Sun11 1:11.11 rtsold: system.syslog (rtsold)
root 19510 0.0 0.0 20820 9608 - Is 01:18 0:00.01 sshd-session: root [priv] (sshd-session)
root 22894 0.0 0.0 13800 2444 - Is Sun11 0:00.00 /usr/local/sbin/dhcp6c -c /var/etc/dhcp6c.conf -p /var/run/dhcp6c.pid
root 25597 0.0 0.0 28392 14784 - S Sun11 0:22.39 /usr/local/bin/python3 /usr/local/opnsense/scripts/syslog/lockout_handler (python3.11)
root 27578 0.0 0.0 24572 9608 - I Sun11 0:00.00 /usr/local/sbin/syslog-ng -f /usr/local/etc/syslog-ng.conf -p /var/run/syslog-ng.pid
root 28327 0.0 0.0 45724 14512 - Ss Sun11 0:36.99 /usr/local/sbin/syslog-ng -f /usr/local/etc/syslog-ng.conf -p /var/run/syslog-ng.pid
root 29000 0.0 0.0 23836 11240 - S Sun11 0:09.05 /usr/local/sbin/lighttpd -f /usr/local/etc/lighttpd_webgui/lighttpd.conf
root 29304 0.0 0.1 54044 27880 - Is Sun11 0:00.01 /usr/local/bin/php-cgi
root 30120 0.0 0.1 54044 27884 - Is Sun11 0:00.01 /usr/local/bin/php-cgi
root 30881 0.0 0.1 54044 27888 - Is Sun11 0:00.01 /usr/local/bin/php-cgi
root 30885 0.0 0.1 54044 27876 - Is Sun11 0:00.01 /usr/local/bin/php-cgi
root 31260 0.0 0.1 59740 33484 - I Sun11 0:00.27 /usr/local/bin/php-cgi
root 31709 0.0 0.1 54108 30000 - I Sun11 0:00.23 /usr/local/bin/php-cgi
root 31825 0.0 0.1 59740 33380 - I Sun11 0:00.03 /usr/local/bin/php-cgi
root 32353 0.0 0.1 54044 27888 - I Sun11 0:00.00 /usr/local/bin/php-cgi
root 33135 0.0 0.1 54044 27888 - I Sun11 0:00.00 /usr/local/bin/php-cgi
root 33755 0.0 0.1 59740 33624 - I Sun11 0:00.51 /usr/local/bin/php-cgi
root 34134 0.0 0.1 59740 33492 - I Sun11 0:00.43 /usr/local/bin/php-cgi
root 34243 0.0 0.1 54044 27888 - I Sun11 0:00.00 /usr/local/bin/php-cgi
_dhcp 34747 0.0 0.0 14080 2716 - ICs Tue07 0:00.03 dhclient: ix0 (dhclient)
root 34975 0.0 0.1 54044 27888 - I Sun11 0:00.00 /usr/local/bin/php-cgi
root 35669 0.0 0.1 54044 27888 - I Sun11 0:00.00 /usr/local/bin/php-cgi
root 36756 0.0 0.1 54044 27892 - I Sun11 0:00.00 /usr/local/bin/php-cgi
root 37327 0.0 0.1 54044 27892 - I Sun11 0:00.00 /usr/local/bin/php-cgi
root 37432 0.0 0.1 54044 27892 - I Sun11 0:00.00 /usr/local/bin/php-cgi
root 37689 0.0 0.1 60012 34448 - I Sun11 0:00.22 /usr/local/bin/php-cgi
root 38994 0.0 0.0 20276 8056 - Is Sun11 0:00.01 sshd: /usr/local/sbin/sshd [listener] 0 of 10-100 startups (sshd)
root 39656 0.0 0.1 57900 31808 - I Sun11 0:01.10 /usr/local/bin/php-cgi
root 40089 0.0 0.1 54044 27880 - I Sun11 0:00.00 /usr/local/bin/php-cgi
root 41073 0.0 0.0 20820 9880 - S 01:19 0:00.03 sshd-session: root@pts/0 (sshd-session)
root 44513 0.0 0.0 13756 2184 - Ss Sun11 1:06.97 /usr/sbin/powerd -b hadp -a hadp -n hadp
root 49625 0.0 0.1 62060 36256 - I 20:41 0:00.34 /usr/local/bin/php-cgi
root 60116 0.0 0.0 14044 2560 - Ss Tue07 0:14.70 /usr/local/sbin/filterlog -i pflog0 -p /var/run/filterlog.pid
root 60772 0.0 0.1 64032 34268 - I Sun11 0:00.66 /usr/local/bin/php-cgi
root 70558 0.0 0.0 14108 2924 - Ss Tue07 0:06.95 /usr/local/sbin/miniupnpd -f /var/etc/miniupnpd.conf -P /var/run/miniupnpd.pid
root 73029 0.0 0.0 24116 8436 - Ss Tue07 0:05.65 /usr/local/sbin/ntpd -g -c /var/etc/ntpd.conf
root 74742 0.0 0.0 13780 2224 u0 Is+ Sun11 0:00.00 /usr/libexec/getty 3wire.115200 ttyu0
root 71039 0.0 0.0 13780 2232 v0 Is+ Sun11 0:00.00 /usr/libexec/getty Pc ttyv0
root 71516 0.0 0.0 13780 2232 v1 Is+ Sun11 0:00.00 /usr/libexec/getty Pc ttyv1
root 72110 0.0 0.0 13780 2220 v2 Is+ Sun11 0:00.00 /usr/libexec/getty Pc ttyv2
root 72405 0.0 0.0 13780 2224 v3 Is+ Sun11 0:00.00 /usr/libexec/getty Pc ttyv3
root 73149 0.0 0.0 13780 2228 v4 Is+ Sun11 0:00.00 /usr/libexec/getty Pc ttyv4
root 73266 0.0 0.0 13780 2224 v5 Is+ Sun11 0:00.00 /usr/libexec/getty Pc ttyv5
root 73910 0.0 0.0 13780 2220 v6 Is+ Sun11 0:00.00 /usr/libexec/getty Pc ttyv6
root 74352 0.0 0.0 13780 2228 v7 Is+ Sun11 0:00.00 /usr/libexec/getty Pc ttyv7
root 41267 0.0 0.0 14312 2708 0 Is 01:19 0:00.00 /bin/sh /usr/local/sbin/opnsense-shell
root 51157 0.0 0.0 17352 4276 0 S 01:19 0:00.02 /bin/csh
root 54081 0.0 0.0 14384 3020 0 R+ 01:19 0:00.00 ps auxUSER COMMAND PID FD PROTO LOCAL ADDRESS FOREIGN ADDRESS
root sshd-sessi 41073 9 stream (not connected)
root sshd-sessi 19510 9 stream (not connected)
root php-cgi 49625 0 stream /var/lib/php/tmp/php-fastcgi.socket-3
root php-cgi 17259 0 stream /var/lib/php/tmp/php-fastcgi.socket-2
root ntpd 73029 20 udp6 *:123 *:*
root ntpd 73029 21 udp4 *:123 *:*
root ntpd 73029 22 udp6 fe80::4adf:37ff:fee4:d26c%ix0:123 *:*
root ntpd 73029 23 udp4 24.62.111.35:123 *:*
root ntpd 73029 24 udp4 10.0.0.1:123 *:*
root ntpd 73029 25 udp6 fe80::4adf:37ff:fee4:d26d%ix1:123 *:*
root ntpd 73029 26 udp6 ::1:123 *:*
root ntpd 73029 27 udp6 fe80::1%lo0:123 *:*
root ntpd 73029 28 udp4 127.0.0.1:123 *:*
root miniupnpd 70558 6 tcp6 *:2189 *:*
root miniupnpd 70558 8 tcp4 *:2189 *:*
root miniupnpd 70558 9 udp4 *:1900 *:*
root miniupnpd 70558 10 udp4 10.0.0.1:16429 *:*
root miniupnpd 70558 12 udp4 10.0.0.1:5351 *:*
root php-cgi 15867 0 stream /var/lib/php/tmp/php-fastcgi.socket-3
root php-cgi 60772 0 stream /var/lib/php/tmp/php-fastcgi.socket-2
root php-cgi 40089 0 stream /var/lib/php/tmp/php-fastcgi.socket-3
root php-cgi 39656 0 stream /var/lib/php/tmp/php-fastcgi.socket-3
root php-cgi 37689 0 stream /var/lib/php/tmp/php-fastcgi.socket-3
root php-cgi 37432 0 stream /var/lib/php/tmp/php-fastcgi.socket-2
root php-cgi 37327 0 stream /var/lib/php/tmp/php-fastcgi.socket-2
root php-cgi 36756 0 stream /var/lib/php/tmp/php-fastcgi.socket-2
root php-cgi 35669 0 stream /var/lib/php/tmp/php-fastcgi.socket-1
root php-cgi 34975 0 stream /var/lib/php/tmp/php-fastcgi.socket-1
root php-cgi 34243 0 stream /var/lib/php/tmp/php-fastcgi.socket-1
root php-cgi 34134 0 stream /var/lib/php/tmp/php-fastcgi.socket-1
root php-cgi 33755 0 stream /var/lib/php/tmp/php-fastcgi.socket-1
root php-cgi 33135 0 stream /var/lib/php/tmp/php-fastcgi.socket-0
root php-cgi 32353 0 stream /var/lib/php/tmp/php-fastcgi.socket-0
root php-cgi 31825 0 stream /var/lib/php/tmp/php-fastcgi.socket-0
root php-cgi 31709 0 stream /var/lib/php/tmp/php-fastcgi.socket-0
root php-cgi 31260 0 stream /var/lib/php/tmp/php-fastcgi.socket-0
root php-cgi 30885 0 stream /var/lib/php/tmp/php-fastcgi.socket-3
root php-cgi 30881 0 stream /var/lib/php/tmp/php-fastcgi.socket-2
root php-cgi 30120 0 stream /var/lib/php/tmp/php-fastcgi.socket-1
root php-cgi 29304 0 stream /var/lib/php/tmp/php-fastcgi.socket-0
root lighttpd 29000 7 tcp4 *:443 *:*
root lighttpd 29000 8 tcp6 *:443 *:*
root lighttpd 29000 9 tcp4 *:80 *:*
root lighttpd 29000 10 tcp6 *:80 *:*
root sshd 38994 6 tcp6 fe80::4adf:37ff:fee4:d26d%ix1:22 *:*
root sshd 38994 7 tcp6 2601:18a:8080:f8:4adf:37ff:fee4:d26d:22 *:*
root sshd 38994 8 tcp4 10.0.0.1:22 *:*
root sshd 38994 9 tcp6 fe80::1%lo0:22 *:*
root sshd 38994 10 tcp6 ::1:22 *:*
root sshd 38994 11 tcp4 127.0.0.1:22 *:*
root dhcp6c 22894 6 udp6 *:546 *:*
root syslog-ng 28327 20 dgram /var/run/log <-
root syslog-ng 28327 21 dgram /var/run/logpriv
root syslog-ng 28327 22 dgram /var/dhcpd/var/run/log
root syslog-ng 28327 23 dgram /var/unbound/var/run/log
root syslog-ng 28327 27 stream /var/db/syslog-ng.ctl
root devd 1061 6 stream /var/run/devd.pipe
root devd 1061 7 seqpac /var/run/devd.seqpacket.pipe
root python3.11 387 3 stream /var/run/configd.socket
root python3.11 387 9 stream /var/run/configd.socket
root python3.11 387 10 stream /var/run/configd.socket
root python3.11 387 13 stream /var/run/configd.socket
root python3.11 387 16 stream /var/run/configd.socket
root python3.11 387 18 stream /var/run/configd.socket
root python3.11 387 25 stream /var/run/configd.socket
Encountered the same issue. Looks like some sort of bug. If Service->ISC DHCPv6->[LAN] "Enable DHCPv6 server on LAN interface" is UNCHECKED FIRST, then Interfaces->[LAN] "IPv6 Configuration Type" cannot be set from "Track Interface" to "None" with the error "The DHCPv6 Server is active on this interface and it can be used only with a static IPv6 configuration. Please disable the DHCPv6 Server service on this interface first, then change the interface configuration.". However, based on the GUI the DHCPv6 Server is not actually running. In such a state XML configuration file shows:
<dhcpdv6>
<lan>
<ramode>disabled</ramode>
<enable>-1</enable>
</lan>
</dhcpdv6>
However, if the Service->ISC DHCPv6->[LAN] "Enable DHCPv6 server on LAN interface" is left CHECKED, then changing Interfaces->[LAN] "IPv6 Configuration Type" to "None" is possible without any error. After these changes XML configuration file shows:
<dhcpdv6>
<lan>
<ramode>disabled</ramode>
</lan>
</dhcpdv6>
That is strange. I'm not sure why that happens, but at least it seems there's a solution: enable ISC DHPv6, then disable Track Interface, then disable ISC DHCPv6.
Maybe @franco or @Monviech can explain this. I migrated off of ISC already before 25.7 and didn't notice anything like this although I was never using DHCPv6 on LAN.
Seems like the issue has been present since at least OPNsense 25.1.9_2 based on https://github.com/opnsense/core/issues/8838 (https://github.com/opnsense/core/issues/8838)
The solution is more like enable ISC DHCPv6, then disable "Track Interface" and that is it because after setting Interfaces->[LAN] "IPv6 Configuration Type" to "None", [LAN] under Services->ISC DHCPv6 no longer exists, so no way to disable the flag. Maybe that is by design? Since DHCPv6 server is not running according to the GUI.
Although the XML configuration stays the same as if DHCPv6 was enabled.
Quote from: OPNenthu on Today at 06:20:08 PMThat is strange. I'm not sure why that happens, but at least it seems there's a solution: enable ISC DHPv6, then disable Track Interface, then disable ISC DHCPv6.
Maybe @franco or @Monviech can explain this. I migrated off of ISC already before 25.7 and didn't notice anything like this although I was never using DHCPv6 on LAN.
I can confirm this is a successful workaround, specifically:
1. Enabled ISC DHCPv6 for my [LAN] interface
2. Under the [LAN] interface I could then change "IPv6 Configuration Type" from "Track Interface" to "None" and save and apply the changes
3. Going back to ISC DHCPv6 there was no longer a [LAN] interface there (only "Leases", which is empty), so there is nothing further to disable