[Bug] Cannot working if under retry

[Kenith]

Hello,

The requests-ntlm is not working if the requets is under retry:

import requests
from requests.packages.urllib3.util.retry import Retry
from requests.adapters import HTTPAdapter
from requests_ntlm import HttpNtlmAuth

retries = Retry(total=1,
                read=1,
                connect=1,
                backoff_factor=1,
                status_forcelist=[500, 502, 503, 504, 407, 403, 401])

session = requests.Session()
session.verify = False
session.mount('http://', HTTPAdapter(max_retries=retries))
session.mount('https://', HTTPAdapter(max_retries=retries))

session.auth = HttpNtlmAuth('GLOBAL\\***', '***')
res = session.get('https://***.corp.***.com/owa/')

print res.status_code

[Kenith]

Found the cause:

because in my status_forcelist, there is: 401.
I removed it, works.

But why with the 401, the request-ntlm not working?

[jborean93]

Probably because NTLM authentication relies on receiving 401 responses. It works like

• Send un authenticated request
• Receive 401 response with header that lists supported auth mechanisms
• Send NTLM negotiate message
• Receive 401 response with NTLM challenge message
• Send NTLM authenticate message
• Receive 200 response as user is now authenticated.

I don't know how the Retry operations change the behaviour but it could be that it adds a hook to 401 responses and continues to try and send the same message (retry) without any of the NTLM messages.