I've been a happy user of dnsmasq on my SOHO LAN for years, providing both DNS services and dhcp services.
However, after switching to AT&T's fiber service, I need to separate responsibility for dhcp and DNS. That's because AT&T requires you to use their router as an interface to their network, and, while you can configure their router's dhcp service, you can't turn it off (you can also configure their router to act as a passthru to your LAN, but that doesn't work well; as in, your connection speed drops 95%).
I could simply not have a DNS running locally. But I find it convenient to access various LAN resources by name, rather than IP address.
My understanding is dnsmasq will not serve as a dhcp server if you don't configure any of the dhcp options. But what I want to do, I think, is a little different: I want dnsmasq to "learn" what IP address was assigned by the AT&T router to a device and then link that IP address to a user-defined host name. If this is possible, I imagine it would be via MAC address.
I don't know if this is possible, and so would appreciate some advice. Or an alternative solution that accomplishes the same thing.