"Microsoft DNS Client" vs. getaddrinfo?

Question

Right now, my application is using the c-ares asynchronous DNS resolver library on Windows below cURL, and I have users complaining that it behaves differently from other windows apps. One particular user said that "other applications are using the Microsoft DNS client" and experiences no problems.

cURL itself has an asynchronous DNS implementation that uses getaddrinfo() in a thread. My guess is that would be equivalent behavior to using the "DNS Client" and its host of functions (e.g. DnsQuery?)

So, dear Lazyweb, I ask if there is a tangible difference between the behavior of getaddrinfo() vs. using the actual Dns* APIs from the Win32 API.

Answer 1

Looking at the sources it seems ares actually implements the dns protocol for querying host names (and doesn't directly call getaddrinfo) - I'd expect that to miss out on things like WINS lookups, and god knows what other kind of stuff windows can do to look up names.

Answer 2

The easiest way to do DNS queries on Windows is to use DNSQuery (and derivated functions, utf8, wbytes, ansi). Unless you need asynchronous resolution, in this case I would recommend to keep using c-ares or other similar API.

I'm not sure about WINS or other windows specific resolution (not part of DNS specs) not being covered by c-ares. It would help if you can give us some examples, maybe we can get them implemented in c-ares as well.