On the following routers:
* Sky Sagem
* TP Link running openwrt
* Ubiquiti Bullet M2 running AirOS

When I do, for example:
nslookup My-iPad
or
ping My-iPad

I get the DHCP assigned IP address for my iPad (named My iPad) returned from the router's DNS. I presume this is some interaction between the DHCP server and the DNS?

However this doesn't seem to work with my DrayTek 2862 (currently on 3.9.0), or any previous firmware. At least as far as I am aware.
I can see my devices listed in the DHCP Table on the DrayTek, and I have my DNS configured to point at the DrayTek, which is successfully forwarding and resolving external names to my ISPs DNS servers. Just no local DNS resolution as per the other products I listed.

I know I could allocate static addresses, and then configure the DrayTek via Application LAN DNS. But then I'd have to add my IP addresses manually and maintain them.

Am I missing something, or does the DrayTek firmware not support this function?
Also, does this "feature" (on other products) have a name? It's hard to Google for it when you don't know what it's called!

Thanks.

Okay, answering my own question - sort of. Dynamic DNS seems to cover it.

So I was aware of Dynamic DNS, but mainly for updating non-static IP addresses to public DNS in order to make those servers accessible from the public internet. This seems to be the focus of the Applications -> Dynamic DNS configuration on the DrayTek.

My question still remains - how to update the DrayTek's local DNS automatically with local clients RFC 1918 addresses assigned from DHCP?