Fix various wide-area-dns limitations

[pemensik]

In PR #577 wide area resolution were disabled. While I admit current state is far from well tested, this feature seems interesting for me. Basic functionality can be tested on dns-sd.org and zeroconf.org domains.

But I agree combinations between mDNS and (wide-area) DNS need better analysis and maybe at least some design. This is area, where I can offer help. Unicast DNS belongs to my area of expertise.

But it would need multiple limitations fixed. Nothing just one PR with few modifications can fix enough.

[evverx]

Agreed. It would be great to support the unicast DNS properly.

There are already issues where some things are tracked: #239 , #254 but given that that part effectively hasn't been updated since 2007 (apart from a commit fixing a huge memory leak) it's safe to say that it's far from what DNS looks like today unfortunately.