Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
Whenever a web request is made by Visual Studio to TFS, Fiddler will show a 401 Unauthorized error. Visual Studio will then try again with a proper Authorization Negotiate header in place with which TFS will respond with the proper data and a 200 status code.
How can I get the correct headers to be sent the first time to stop the 401?
This is how the process of Windows Integrated Authentication (NTLM) works. NTLM is a connection based authentication mechanism and actually involves 3 calls to establish the authenticated session.
The TFS API then goes to extra-ordinary lengths to make sure that this handshake is done in the most efficient way possible. It will keep the authenticated connection open for a period of time to avoid this hand-shake where possible. It will also do the initial authentication using a HTTP payload with minimal content and then send the real message if the message you were going to send is over a certain length. It does a bunch of other tricks as well to optimise the connection to TFS.
Basically, I would just leave it alone as it works well.