title: Cannot authenticate into mongo, "auth fails"
body: <p>I've created an admin user for mongo using these directions:</p>
  
  <p><a href="http://docs.mongodb.org/manual/tutorial/add-user-administrator/" rel="noreferrer">http://docs.mongodb.org/manual/tutorial/add-user-administrator/</a></p>
  
  <p>From the mongo client it looks like I can authenticate:</p>
  
  <pre><code>&gt; use admin
  switched to db admin
  &gt; db.auth('admin','SECRETPASSWORD');
  1
  &gt;
  </code></pre>
  
  <p>But I can't connect any other way. For example:</p>
  
  <blockquote>
    <p>mongo -u admin -p SECRETPASSWORD</p>
  </blockquote>
  
  <p>gives the error:</p>
  
  <pre><code>JavaScript execution failed: Error: 18 { code: 18, ok: 0.0, errmsg: "auth fails" } at src/mongo/shell/db.js:L228
  </code></pre>
  
  <p>I have <code>auth = true</code> in <code>etc/mongod.conf</code>.</p>
  
  <p>What am I missing?</p>