Text only | Text with Images

OPNsense Forum

English Forums => 26.1, 26,4 Series => Topic started by: nero355 on January 28, 2026, 12:14:30 AM

Title: [ISC vs. KEA] Is the effect of this DHCP option the same for both or not ?
Post by: nero355 on January 28, 2026, 12:14:30 AM
I was wondering if the following two function the same way or not :

ISC has : Ignore Client UIDs
QuoteBy default, the same MAC can get multiple leases if the requests are sent using different UIDs. To avoid this behavior, check this box and client UIDs will be ignored.

KEA has : Match client-id
QuoteBy default, KEA uses client-identifiers instead of MAC addresses to locate clients, disabling this option changes back to matching on MAC address which is used by most dhcp implementations.

I had the ISC option Enabled so now I have the KEA option Disabled and was wondering if the result is the same :

Ignore Clients sending anything else than their MAC Address when requesting a DHCP Lease ?!



I have tried reading about it in the KEA Documentation on their website, but there was nothing related to this that I could find...
Title: Re: [ISC vs. KEA] Is the effect of this DHCP option the same for both or not ?
Post by: nero355 on February 01, 2026, 06:25:34 PM
** BUMP **

I am really curious if this is the case or not :

I really liked the ISC DHCP option and hope the KEA DHCP option does the same :)
Title: Re: [ISC vs. KEA] Is the effect of this DHCP option the same for both or not ?
Post by: nero355 on February 23, 2026, 09:58:24 PM
** BUMP **

Attempt to get any info about this #3 :)



I am really curious if this works the way I think it does ?!
Title: Re: [ISC vs. KEA] Is the effect of this DHCP option the same for both or not ?
Post by: Patrick M. Hausen on February 23, 2026, 10:23:11 PM
I can only say as much:

Without "ignore client UIDs" checked reservations based on MAC addresses do not work in Kea. I only want to care about MAC addresses, no idea what these UIDs even are and honestly do not care. MAC address --> IP address. Like DHCP has always worked.

HTH
Patrick
Title: Re: [ISC vs. KEA] Is the effect of this DHCP option the same for both or not ?
Post by: nero355 on February 24, 2026, 01:52:17 PM
Quote from: Patrick M. Hausen on February 23, 2026, 10:23:11 PMWithout "ignore client UIDs" checked reservations based on MAC addresses do not work in Kea.
Unchecked you get this :
QuoteMAC address --> IP address. Like DHCP has always worked.

Checked allows all the different "Alternative ID methods" a.k.a. Mobile Phones generating random MAC Addresses and flooding your DHCP Pool with nonsense that should not even be allowed to exist...

QuoteI only want to care about MAC addresses, no idea what these UIDs even are and honestly do not care.
AFAIK they are fake MAC Addresses and that's why I want to know more about this setting : Does it prevent what I think it will prevent ?!
Title: Re: [ISC vs. KEA] Is the effect of this DHCP option the same for both or not ?
Post by: Patrick M. Hausen on February 24, 2026, 02:47:24 PM
I apologize - I wrote nonsense because I confused the "Ignore Client UIDs" and Kea's "Match client-id".

I have "Match client-id" unchecked, because otherwise static assignments based on MAC address do not work. Unfortunately that's how far my experience with DHCP reaches.
Title: Re: [ISC vs. KEA] Is the effect of this DHCP option the same for both or not ?
Post by: nero355 on February 25, 2026, 12:18:21 AM
Quote from: Patrick M. Hausen on February 24, 2026, 02:47:24 PMI apologize - I wrote nonsense because I confused the "Ignore Client UIDs" and Kea's "Match client-id".
No worries, I thought so :)

QuoteI have "Match client-id" unchecked, because otherwise static assignments based on MAC address do not work.
That's how I have got it here too for a while now.
Text only | Text with Images