系统注册失败，并显示 "Name 或 service not known"

Issue

• 系统注册失败，并显示错误 Name or service not known ：

  Error communicating with server. The message was:
  Name or service not known
  

• 无法注册系统，其失败并显示错误 gaierror: [Errno -2] Name or service not known :

  2014-06-18 14:33:50,133 [ERROR]  @managercli.py:151 - Error during registration: [Errno -2] Name or service not known
  2014-06-18 14:33:50,134 [ERROR]  @managercli.py:152 - [Errno -2] Name or service not known
  Traceback (most recent call last):
    File "/usr/share/rhsm/subscription_manager/managercli.py", line 1045, in _do_command
      owner_key = self._determine_owner_key(admin_cp)
    File "/usr/share/rhsm/subscription_manager/managercli.py", line 1148, in _determine_owner_key
      owners = cp.getOwnerList(self.username)
    File "/usr/lib64/python2.6/site-packages/rhsm/connection.py", line 852, in getOwnerList
      return self.conn.request_get(method)
    File "/usr/lib64/python2.6/site-packages/rhsm/connection.py", line 541, in request_get
      return self._request("GET", method)
    File "/usr/lib64/python2.6/site-packages/rhsm/connection.py", line 448, in _request
      conn.request(request_type, handler, body=body, headers=headers)
    File "/usr/lib64/python2.6/httplib.py", line 914, in request
      self._send_request(method, url, body, headers)
    File "/usr/lib64/python2.6/httplib.py", line 951, in _send_request
      self.endheaders()
    File "/usr/lib64/python2.6/httplib.py", line 908, in endheaders
      self._send_output()
    File "/usr/lib64/python2.6/httplib.py", line 780, in _send_output
      self.send(msg)
    File "/usr/lib64/python2.6/httplib.py", line 739, in send
      self.connect()
    File "/usr/lib64/python2.6/site-packages/M2Crypto/httpslib.py", line 51, in connect
      socket.getaddrinfo(self.host, self.port, 0, socket.SOCK_STREAM):
  gaierror: [Errno -2] Name or service not known
  

• yum update 失败，并显示 Error communicating with server。消息是 Name or service unknown