Estou tentando abrir e analisar uma página html. No python 2.7.8, não tenho nenhum problema:

import urllib
url = "https://ipdb.at/ip/66.196.116.112"
html = urllib.urlopen(url).read()

e está tudo bem. No entanto, quero passar para o python 3.4 e recebo o erro HTTP 403 (Proibido). Meu código:

import urllib.request
html = urllib.request.urlopen(url) # same URL as before

File "C:\Python34\lib\urllib\request.py", line 153, in urlopen
return opener.open(url, data, timeout)
File "C:\Python34\lib\urllib\request.py", line 461, in open
response = meth(req, response)
File "C:\Python34\lib\urllib\request.py", line 574, in http_response
'http', request, response, code, msg, hdrs)
File "C:\Python34\lib\urllib\request.py", line 499, in error
return self._call_chain(*args)
File "C:\Python34\lib\urllib\request.py", line 433, in _call_chain
result = func(*args)
File "C:\Python34\lib\urllib\request.py", line 582, in http_error_default
raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 403: Forbidden

Funciona para outros URLs que não usam https.

url = 'http://www.stopforumspam.com/ipcheck/212.91.188.166'

está bem