DHCP on the Pace 5268AC router
I have ATT GigaPower, and a bunch of questions/problems with DHCP on the Pace 5268AC router.
First - is there a way to reserve a specific local IP address for a device in advance? There doesn't appear to be a way to do that unless the device has already connected and recieved an IP. I don't see any way to just enter a MAC address and an IP reservation the way typical DHCP servers do.
Second - if the device has connected once, lets say at 192.168.1.101, I can then go in to Settings/LAN/LAN IP Address Allocation, find its MAC address and change it from "Private from pool: 192.168.1.0" to "Private Fixed: 192.168.201" or whatever. After hitting Save, the device details and device status screens show the new IP address for that MAC address. But when I check the device (a Win10 PC), it is still using the old IP. A release and renew on the PC just pulls the old IP again; what should happen is that the router send a DHCP NACK indicating that the old IP is no longer available for lease, so the device requests a new one. I get the same behavior for iOS and Linux devices. Why didn't this work?
A few eventually changed, hours later - I get the impression that the router just does nothing until the original lease expires, but I can't wait 24 hours every time I change an IP, and the shortest lease period that can be configured is 1 hour.
After messing about with this for nearly an hour, I cleared the IP address table, thinking that would clear the leases. But it also cleared the reservations. Worse, all of the devices that had pulled a lease earlier now show as "Static IP" and can't be changed. The static IP they show, of course, is the one the router handed out as DHCP in the first place (for the Win10 PC, it shows 192.168.1.101, which still works).
So the third question is, how do I clear the lease table without flushing all of my reservations? Power cycling the router doesn't do it.
And I now have a fourth question - how do I get the router to treat these as DHCP devices again, instead of static? I no longer have the option of changing them to DHCP, or changing the IP address that they are using. It also no longer shows the device names, although for anything that comes up as Static, I now have the option of keying them in manually (I can't for a DHCP device).
So that brings up a fifth question - why can't I set the device name on a DHCP device, but I can on a "static" device? Both have existing names and have the same dynamic DNS update behavior - in fact, the devices haven't changed, only the router changed. Normally, I would prefer the device host name, but I have a few devices (like a Nest thermostat) that uses the serial number or other obscure value as a hostname and can't be changed, making it fairly useless for me. The alternative is to modify DNS for forward and reverse lookups and fix it there, but since the router IS the local DNS and refuses to allow me to change it, I can't.
Any ideas? Thanks.