Reverse Proxy with Kerberos pre authentication

Hi,

is it possible to make with NGINX a reverse proxy with kerberos auth?
NGINX should do all the authentication stuff, so the user don´t talk directly with the kerberos server.

The goal is:
- the user connect to webmail.example.com
- a authentication Windows pops up
- the user types the login information
- nginx do all the auth stuff
- the user directly login to the webmail without second authentication.

thanks