avoid parallel lookups for same name

[pforemski]

During today's DynDNS outage I noticed dingo will issue a query for the same name in all threads given enough applications ask for it (eg. github.com). We should avoid this, eg by letting the query go back / timeout before trying in another thread.

[heri16]

Is having dnsmasq fronting dingo an alright setup to avoid bloat and less-scalable computational requirements? would this subject dingo to a DoS attack surface?