It starts, produces an error message, and stops:

    tinydns: fatal: unable to bind UDP socket: address not available
Now the wisdom on the web indicates that I've got something runnin  that
has already taken port 53.
How do I find out what?
The usual command lsof -i udp:53 finds nothing.
I have removed connman.
I have killalled dnscache.
I don't know what to get rid of next.
Apparently there's a possibility something is waiting for input on port 53
but has not got a connection yet, so tinydns can't get it.

I have got a physical wired ethernet connected, and have assigned it a
local IP number.
It's good enough that I can connect to the laptop from outside using ssh,
as long as I connect with an IP number. So I know the wired connection
works.
I haven't yet tried connecting from outside my LAN.

What next?