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English Forums => 26.1 Series => Topic started by: staticznld on February 05, 2026, 10:46:14 AM

Title: Prefix delegations when PD is not enabled in ISC DHCPv6
Post by: staticznld on February 05, 2026, 10:46:14 AM
When looking in "Services - ISC DHCPv6 - Leases - Delegated Prefixes", I noticed that a prefix had been delegated.
My LAN interface is tracking the WAN interface with prefix ID "AAAA", with manual configuration turned off.

When checking /var/log/dhcpd/latest.log, I saw the delegated prefix as shown below:

<190>1 2026-02-05T05:37:11+01:00 firewall.redacted.com dhcpd 71898 - [meta sequenceId="2"] Reply NA: address 2a02:REDA:CTED:aaaa::1245 to client with duid 00:02:00:00:ab:11:1c:2f:ae:81:d3:02:e2:c3 iaid= 146797512 valid for 7200 seconds
<190>1 2026-02-05T05:37:11+01:00 firewall.redacted.com dhcpd 71898 - [meta sequenceId="3"] Reply PD: address 2a02:REDA:CTED:ff00::/60 to client with duid 00:02:00:00:ab:11:1c:2f:ae:81:d3:02:e2:c3 iaid = 146797512 valid for 7200 seconds

How is it possible that a prefix is delegated when all related options are turned off?
The device requesting the prefix is a hardware Globalping probe.
Title: Re: Prefix delegations when PD is not enabled in ISC DHCPv6
Post by: miketubby on February 05, 2026, 12:11:45 PM
I have no idea how that happened, but I took the hint and moved over the Kea DHCP as ISC DHCP is End-of-Life and deprecated.
Title: Re: Prefix delegations when PD is not enabled in ISC DHCPv6
Post by: staticznld on February 05, 2026, 12:15:25 PM
That's why I saw that a prefix was delegated.
I'm also looking into switching to Kea or dnsmasq in the near future.
Title: Re: Prefix delegations when PD is not enabled in ISC DHCPv6
Post by: franco on February 05, 2026, 12:27:43 PM
> My LAN interface is tracking the WAN interface with prefix ID "AAAA", with manual configuration turned off.

If I interpret this correct "manual configuration" off means "automatic configuration" on.  Part of this is distributing PDs when your WAN prefix is big enough.


Cheers,
Franco
Title: Re: Prefix delegations when PD is not enabled in ISC DHCPv6
Post by: staticznld on February 05, 2026, 12:34:36 PM
See the attached screenshot for the LAN settings.
I thought that when "Manual configuration" is turned off, only radvd distributes IPv6 addresses.

I am assigned a /48 prefix by my ISP.