title: Getting the following error "Datanode denied communication with namenode" while configuring hadoop 0.23.8
body: <p>I am trying to configure hadoop 0.23.8 on my macbook and am running in with the following exception</p>
  
  <pre><code>org.apache.hadoop.hdfs.server.protocol.DisallowedDatanodeException: Datanode denied communication with namenode: 192.168.1.13:50010
  at org.apache.hadoop.hdfs.server.blockmanagement.DatanodeManager.registerDatanode(DatanodeManager.java:549)
  at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.registerDatanode(FSNamesystem.java:2548)
  at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.registerDatanode(NameNodeRpcServer.java:784)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
  at java.lang.reflect.Method.invoke(Method.java:597)
  at org.apache.hadoop.ipc.WritableRpcEngine$Server.call(WritableRpcEngine.java:394)
  at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1571)
  at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1567)
  at java.security.AccessController.doPrivileged(Native Method)
  at javax.security.auth.Subject.doAs(Subject.java:396)
  at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1262)
  at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1565)
  </code></pre>
  
  <p>My core-site.xml looks like this </p>
  
  <pre><code>&lt;configuration&gt;
  &lt;property&gt;
  &lt;name&gt;dfs.federation.nameservices&lt;/name&gt;
  &lt;value&gt;ns1&lt;/value&gt;
  &lt;/property&gt;
  
  &lt;property&gt;
  &lt;name&gt;dfs.namenode.rpc-address.ns1&lt;/name&gt;
  &lt;value&gt;192.168.1.13:54310&lt;/value&gt;
  &lt;/property&gt;
  
  &lt;property&gt;
  &lt;name&gt;dfs.namenode.http-address.ns1&lt;/name&gt;
  &lt;value&gt;192.168.1.13:50070&lt;/value&gt;
  &lt;/property&gt;
  
  &lt;property&gt;
  &lt;name&gt;dfs.namenode.secondary.http-address.ns1&lt;/name&gt;
  &lt;value&gt;192.168.1.13:50090&lt;/value&gt;
  &lt;/property&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>Any ideas on what I may be doing wrong?</p>