title: Determining which nameserver performed a resolution
body: <p>I am setting up two nameservers in <code>constr</code> and then using <code>res_search</code> to find the IP address of a URI. </p>
  
  <p>Is there an easy way to find out which of the two nameservers did the resolution?  I know that I can set up a trace in <code>res_search</code> and capture stdout but in my situation that will not be possible.  Is the address of the nameserver somewhere in the result?</p>