使用pip工具时，遇到【ERROR -3】

错误提示：

  Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError(': Failed to establish a new connection: [Errno -3] \xe5\x9f\x9f\xe5\x90\x8d\xe8\xa7\xa3\xe6\x9e\x90\xe6\x9a\x82\xe6\x97\xb6\xe5\xa4\xb1\xe8\xb4\xa5',)': /packages/60/8e/cdcc5c8c97dc4d591dc96b6f452f31393fc1393bd1f37d2819bcce9d0d57/ChatterBot-0.8.7-py2.py3-none-any.whl
  Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError(': Failed to establish a new connection: [Errno -3] \xe5\x9f\x9f\xe5\x90\x8d\xe8\xa7\xa3\xe6\x9e\x90\xe6\x9a\x82\xe6\x97\xb6\xe5\xa4\xb1\xe8\xb4\xa5',)': /packages/60/8e/cdcc5c8c97dc4d591dc96b6f452f31393fc1393bd1f37d2819bcce9d0d57/ChatterBot-0.8.7-py2.py3-none-any.whl
  Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError(': Failed to establish a new connection: [Errno -3] \xe5\x9f\x9f\xe5\x90\x8d\xe8\xa7\xa3\xe6\x9e\x90\xe6\x9a\x82\xe6\x97\xb6\xe5\xa4\xb1\xe8\xb4\xa5',)': /packages/60/8e/cdcc5c8c97dc4d591dc96b6f452f31393fc1393bd1f37d2819bcce9d0d57/ChatterBot-0.8.7-py2.py3-none-any.whl
  Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError(': Failed to establish a new connection: [Errno -3] \xe5\x9f\x9f\xe5\x90\x8d\xe8\xa7\xa3\xe6\x9e\x90\xe6\x9a\x82\xe6\x97\xb6\xe5\xa4\xb1\xe8\xb4\xa5',)': /packages/60/8e/cdcc5c8c97dc4d591dc96b6f452f31393fc1393bd1f37d2819bcce9d0d57/ChatterBot-0.8.7-py2.py3-none-any.whl
  Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError(': Failed to establish a new connection: [Errno -3] \xe5\x9f\x9f\xe5\x90\x8d\xe8\xa7\xa3\xe6\x9e\x90\xe6\x9a\x82\xe6\x97\xb6\xe5\xa4\xb1\xe8\xb4\xa5',)': /packages/60/8e/cdcc5c8c97dc4d591dc96b6f452f31393fc1393bd1f37d2819bcce9d0d57/ChatterBot-0.8.7-py2.py3-none-any.whl
Could not install packages due to an EnvironmentError: HTTPSConnectionPool(host='files.pythonhosted.org', port=443): Max retries exceeded with url: /packages/60/8e/cdcc5c8c97dc4d591dc96b6f452f31393fc1393bd1f37d2819bcce9d0d57/ChatterBot-0.8.7-py2.py3-none-any.whl (Caused by NewConnectionError(': Failed to establish a new connection: [Errno -3] \xe5\x9f\x9f\xe5\x90\x8d\xe8\xa7\xa3\xe6\x9e\x90\xe6\x9a\x82\xe6\x97\xb6\xe5\xa4\xb1\xe8\xb4\xa5',))

天真的我一开始以为是pip工具出问题了，卸载并重装pip后，仔细检查发现是DNS配置出了问题，域名服务器是本机IP地址：127.0.0.1，所以修改域名服务器。

sudo gedit /etc/resolv.conf   #打开DNS编辑器
**在打开的编辑器的最下方，补充一下内容**
nameserver  8.8.8.8           #DNS
nameserver 114.114.114.114    #DNS2

编辑完成后，保存并更新（或关闭当前终端）即可。