Python 2.7.13 does not respect NO_PROXY and makes urllib2.urlopen() error with "Tunnel connection failed: 403 Forbidden"

Question

The following test passes with Python 2.7.11:

def test_urllib(self):
    import urllib2
    import ssl
    context = ssl._create_unverified_context() # service does not have a trusted cert
    url = urllib2.urlopen("https://intranet.adress:port/", context=context)
    url.read()

After upgrade to Python 2.7.13 the test fails with:

python/Lib/urllib2.py", line 1198, in do_open raise URLError(err) URLError: urlopen error Tunnel connection failed: 403 Forbidden

I tried some header and proxy settings, but without any success. I get always the same error. What has changed between Python 2.7.11 and 2.7.13 in SSL authentication?

Answer 1

PS.: Python bug created for this issue. no_proxy content starting with dot (.domain) broken in Python 2.7.13

https://bugs.python.org/issue29142