Messages

[[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

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.

[UNCHECKED FIRST]

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>