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I have a Python program which makes requests using httplib/http.client. It works beautifully in Python 2.7. Both Python2 and Python3 work 100% of the time with http. However, the program fails for some of our named servers using https from Python3.

We have Python 3.9.6 on OS X and Python 3.8.5 on AWS linux.
We have Python 2.7.18 AWS linux.

Here is the specific error I get:

ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: Hostname mismatch, certificate is not valid for '{server name}'. (_ssl.c:1123)

Our IT department uses a wildcard cert for all our named servers in our Dev Cloud. I've double checked. The cert on the server where I'm getting the error matches the cert on a server where the connection from Python3 works.

Here's my code for importing the httplib module:

if PY_VERSION >= 3:
    import http.client as httplib
else:
    import httplib

and for the connection function:

        if self.protocol == 'http':
            self.httpConn = httplib.HTTPConnection
        elif self.protocol == 'https':
            self.httpConn = httplib.HTTPSConnection

and for the connection:

        if self.protocol == 'https':
            self.ssl_context = ssl.create_default_context()
        self.the_conn = self.httpConn(self.site)

What changed from Python2 to Python3 that I can make a successful https connection from Python2, but from Python3 it fails?

As an aside, I tried a different program which uses the requests module and it can communicate with the troublesome server. Unfortunately, that is not a viable solution in this case because requests does not exist in Python2 and I need this program to work for all Python installations.

Christopher Biessener
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  • FWIW "because requests does not exist in Python2" It completely does, you just need to use an older version of it. Other than that the problem is not your code, it just happens you get the "wrong"(?) certificate on some connection attempts. Is the error message really containing `{server name}` or was that your edit? – Patrick Mevzek Mar 17 '23 at 17:21
  • @PatrickMevzek that is my edit – Christopher Biessener Mar 17 '23 at 17:35
  • *"The cert on the server where I'm getting the error matches the cert on a server where the connection from Python3 works."* - is this a typo or do you really have a server where Python 3 works? In this case this does not sound like a difference in the Python version but in the environment were Python is running. – Steffen Ullrich Mar 17 '23 at 21:18
  • @SteffenUllrich I thought the same thing until it happened both from AWS Linux and OS X. – Christopher Biessener Mar 21 '23 at 13:12

0 Answers0