Nginx reverse proxy - passthrough basic authenication - iis

Question

I am trying to setup nginx as a reverse rpoxy server in front off several IIS web servers who are authenticating using Basic authentication.
(note - this is not the same as nginx providing the auth using a password file - it should just be marshelling everythnig between the browser/server)
Its working kind off - but getting repeatedly prompted for auth by every single resource (image/css etc) on a page.
upstream my_iis_server {
server 192.168.1.10;
}
server {
listen 1.1.1.1:80;
server_name www.example.com;
## send request back to my iis server ##
location / {
proxy_pass http://my_iis_server;
proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
proxy_http_version 1.1;
proxy_set_header Connection "";
proxy_pass_header Authorization;
proxy_redirect off;
proxy_buffering off;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}
}

Answer 1

This exact situation took me forever to figure out, but OSS is like that I guess. This post is a year old so maybe the original poster figured it out, or gave up?
Anyway, the problem for me at least was caused by a few things:
IIS expects the realm string to be the same as what it sent to Nginx, but if your Nginx server_name is listening on a different address than the upstream then the server side WWW-Authenticate is not going to be what IIS was expecting and ignore it.
The builtin header module doesn't clear the other WWW-Authenticate headers, particularly the problematic WWW-Authenticate: Negotiate. Using the headers-more module clears the old headers, and adds whatever you tell it to.
After this, I was able to finally push Sharepoint 2010 through Nginx.
Thanks stackoverflow.
server {
listen 80;
server_name your.site.com;
location / {
proxy_http_version 1.1;
proxy_pass_request_headers on;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
#proxy_pass_header Authorization; //This didnt work for me
more_set_input_headers 'Authorization: $http_authorization';
proxy_set_header Accept-Encoding "";
proxy_pass https://sharepoint/;
proxy_redirect default;
#This is what worked for me, but you need the headers-more mod
more_set_headers -s 401 'WWW-Authenticate: Basic realm="intranet.example.com"';
}
}

Answer 2

I had these same symptoms with nginx/1.10.3. I have a service secured under basic authentication, and nginx as a reverse proxy between the clients and the server. The requirement was that nginx would passthrough the authorization.
First request to the server did pass through the Authorization header. Second request simply blocked this header, which meant the client was only able to make one request per session.
This was somehow related to cookies. If I cleared the browser cookies, then the cycle repeated. The client was able to authenticate but just for the first request. Closing the browser had the same effect.
The solution for me was to change the upstream server from https to http, using:
proxy_pass http://$upstream;
instead of:
proxy_pass https://$upstream;