Query the public outbound address for the given address family via OpenDNS; return undefined on failure.
Query mail exchanger records with a default 1-second timeout; return an empty array on query failure.
Query name server records; default to system DNS and a 1-second timeout. Return an empty array on query failure.
Query service discovery records (e.g. _service._tcp.domain); return an empty array on failure.
Query TXT records, each containing multiple text segments; return an empty array on failure.
Resolve IPv4/IPv6 addresses asynchronously; return undefined on failure. With no servers, use the system resolver without applying timeout. With explicit DNS servers, the default timeout is 1 second.
Mail exchanger record.