Pass-through NTLM authentication in a web app on an IMAP mail server
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I'm in need of using NTLM authentication in my web application against an IMAP mail server. Authentication in the web app itself is NTLM too. Thus, the user opens the web app interface and the web server end grabs the inbox of that user on the mail server authenticating via NTLM. Is that possible if I never store (neither I have access to) the user's password?

Is there any way to link the client's browser and the IMAP server via my web app so that token exchange would occur between them and I would just act as a gateway between them. Or, is there any other method to accomplish this task without knowing the password?

The web app can be asp.net/iis or php/apache. Either option will work for me.