OPNsense 26.1.2 (although this was a problem on various 25xx versions)
ISC DHCPV4 (not sure this is relevant)
In order to keep my kids from using private MACs to get internet at night (I have schedules enabled), my lan DHCP scope is a /23. I have my DHCP server set to give IPs out from the second /24. That /24 is blocked in the firewall. Essentially, if a new MAC connects, it won't get internet until I make a DHCP reservation and put the IP in the first /24. This has worked for years up until a few months ago, so I believe this setup is largely irrelevant.
Sometime in the last few months, I started having issues that IPs that I manually assign an IP from the first /24 that "should" have internet, they will not have internet until the firewall is rebooted. This behavior is very odd and I don't think this is normal. Is this a normal setting that I just don't know about, or is something messed up?
Quote from: Amicably6896 on February 16, 2026, 11:26:24 AMkeep my kids from using private MACs to get internet at night
My understanding is/was that those "MACs" aren't actual MACs and that this option in both ISC and KEA would prevent them flooding your DHCP Scope : https://forum.opnsense.org/index.php?topic=50536.0
But no one can tell me if this is indeed true for both and not just ISC and the KEA Documentation on the KEA website doesn't tell me a word about it either...
Hey I appreciate the response, but I think I may have obfuscated the real question by explaining how my setup works.
What I'm trying to sort out is why newly reserved IPs won't get internet until I reboot the firewall. This is new behavior in the last few months or so. I shouldn't have to reboot for a valid DHCP IP to get out to the internet.
Does it work if you just restart the DHCP service?
Quote from: Patrick M. Hausen on February 22, 2026, 02:29:54 PMDoes it work if you just restart the DHCP service?
Sorry, I didnt see your response until now. No, restarting the DHCP v4 service does not allow new DHCP reservations to get internet. In fact, I tried restarting all services shown on the dashboard and still no internet. The only thing that works is to reboot the router which is a 3-4 minute internet outage. It is frustrating for sure.
Likely I will build a second router and re-create all my configs and go thru setting up Kea DHCP since ISC is deprecated anyways.
I suspect that ISC is retaining the dynamic lease, even after a restart. That is also the behavior you will find in Kea at the moment, but it seems it will have a "Delete lease" button very soon, according to https://github.com/opnsense/core/pull/10019 (https://github.com/opnsense/core/pull/10019)
If you want to migrate from ISC to dnsmasq or Kea, you can export your reserves and import them in the new service. Don't forget to deactivate ISC before activating the new DHCP service. No need to reinstall or re-create a new firewall from scratch.