trawson wrote

Should I be able to manage the AP through a wired connection that goes through the network and not direct to the AP?

 

This works, yes. I do this all the time. It even works with static IPs not only outside the DHCP pool, but outside the network's subnet if (and only if) you use static IPs for the EAP and for the computer/laptop.

Example: My network's subnet IP is 192.168.1.0/24. The EAP is set to fixed IP 192.168.0.254, my laptop connected to the switch is usually in the 192.168.1.0 subnet, but if I set it to static IP 192.168.0.10 I can successfully connect to the EAP.

Other things to watch out for: some Windows versions seem to not obey changes from dynamic to static IPs unless the system is rebooted. Consider use of Linux or MacOS (a UNIX system, too); Microsoft(ware) is crap. Also make sure your browser accepts session cookies.

trawson wrote

Thanks. Interesting ... the wired (desktop) machine does have a fixed IP but it is assigned by the router based on MAC address, from Windows' viewpoint it is not fixed. But how would the EAP know or care about that??

It learns this through the ARP (address resolution protocol).

Check wether the wired machine keeps it fixed IP and MAC addresses over the time (i.e. make sure that MAC randomization isn't enabled on your wired device, a technique becoming more and more popular) or whether it falls back to a dynamic IP assigned by DHCP because it probably changes its MAC address regularily due to MAC randomization.

The easiest - and traditional - way of setting a fixed IP address independent of the device's MAC address is to set it up as a true static IP on the device itself. That's what I do even on my laptop by using two different network profiles: one for use when I'm in my office (static IP) and one for use when travelling (dynamic IP assignment by DHCP). Those different profles can be selected very easily on my MacBook.

I even have a third network profile named »TP-Link management« assigning an IP out of the 192.168.0.0/24 subnet to the laptop for initial setup of all kind of TP-Link devices. To use this profile, I connect my laptop to the TP-Link device directly (i.e. not via the network), but after setting up a fixed IP to the TP-Link device once, I can connect to it through the regular network, too.