title: MongoDB+Nodejs reads are not distributed across replicaset members with readpreference as NEAREST
body: <p>I had a replica set with primary/secondary and read preference as NEAREST. Through <em>MongoStat</em>, I can see that requests are going to the replica set member where the mongod instance and nodejs is running and not to the other member on a different aws instance. Pinging is not enabled between the two. I can also verify that the other instance is accessible by changing the read preference. Working fine with my java client. Should the other instance be ping-able for read sharing? SecondaryAcceptableLatencyMS is set at 500.
  Here is the sample code snippet I am trying to execute.</p>
  
  <pre><code>var replSet = new ReplSetServers( [
      new Server( "localhost", 27017, { auto_reconnect: true, native_parser: true, slaveOk: true } ),
      new Server( "&lt;replmem1&gt;", 27017, { auto_reconnect: true, native_parser: true, slaveOk: true } ),
      new Server( "&lt;replmem2&gt;", 27018, { auto_reconnect: true, native_parser: true, slaveOk: true } )
    ],
    {read_secondary:true, secondaryAcceptableLatencyMS:500 }
  );
  
  
  var dbCon = new Db("emails_" + postParams["campaign_id"], replSet, {safe: true, readPreference: mongo.ReadPreference.NEAREST});
      dbCon.open(function(err, db) {
  </code></pre>