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High availability / Re: Unbound DNS registration not working for failover DHCP configuration
« on: April 22, 2022, 11:15:30 pm »It's strange to put it that way when isc-dhcp never supported this. Luckily there are options to use external DHCP servers that can possibly do this. A lot of companies go this route because they have one running and integrated into their network already.
Cheers,
Franco
Yeah, I had no idea about this limitation until yesterday when I posted. I've not worked with HA configurations of Opnsense until Q4 2021. So I'm learning as I go what does/doesn't work well together and how to work around things.
One thing I did find with the 21.7 versions is that if you turned on "promiscuous mode" for that interface, everything seemed to be fine. We tried it as a "well, what do we have to lose if it doesn't work?" and it worked. I have no idea what other consequences there would be for leaving that on 24x7. But as the router is horribly overpowered for its use (and despite having 2500 clients, they'll never have more than about 500Mb/sec of traffic total as they aren't desktops and such with any kind of possible high throughput needs) I figured I'd never have a problem.
Once 22.1 came out then it stopped working, and I just accepted that it didn't work. I have no idea if promiscuous mode should have fixed it or it was just a happy side-affect.
I'm also considering the possibility of setting the failover split to 256. In the event of a failover (planned or unplanned) I could handle the DNS not resolving while all the devices obtain new IPs from the other device.
I'm going to explore the options with promiscuous mode and failover split in more detail this weekend or next week and I'll report back what I find.
I'm going to pm you pmhausen to discuss some things about this in more detail. The company I'm working with may be willing to sponsor this code.