Im new to dude but I cant figure out how to do this

I want to place a "customer" on a map, but the customer has dynamic PPPoe interface that is also dynamic IP address.
I want to somehow link an interface to device, if interface dissapears, then device will go red/down.

I cant see any way to place a device on a map because it wants an IP address.

If the IP is being registered with a DNS server set the device to DNS Lookup "name to address" and set the lookup interval low.

Can mikrotik do this some way? or do I need a separate DNS server?

I think the easiest way for you to deal with this is to ask for a static IP address.

On the remote device can you put a loopback interface and give it a static IP address?
That way you could just monitor the loopback interface... If it is down the PPoE is down.

I doubt you will be able to find a DNS solution since you might not be able to get the name registered.

MikroTik could solve it but I have not seen anything in The Dude that does this already so it would take them quite a bit of work.