S3 & node.js / Define new agent for aws.sdk

I use node.js and aws-sdk.

I want to define a new agent from a require aws-sdk.

  var agent = new http.Agent()
  agent.maxSockets = 20;
  var s3 = new AWS.S3({accessKeyId: "acc",
  secretAccessKey: "sec", region:"us-east-1", httpOptions: {agent: agent}});

For some reason, it gives me an Networking error when I use var download = s3t.getObject(s3Params);

What can be the reason? How I fedined new agent?