I've asked this question on serverfault, where there is a +50 bounty on it currently.
http://serverfault.com/questions/754351/what-is-a-correct-ways-to-allow-login-to-an-iis-site-through-a-reverse-proxy/755659#755659
Basically, when I set up my reverse proxy, it works fine on pages without logins through iis, but if I have a site with iis login (the popup login similar to sharepoint's login), it just continuously asks for the login. There's no failed login attempt in the logs. I have all error logs listed in the serverfault question. Any help is appreciated. If I get a solution on serverfault, I will post the full question, and answer here.
http://serverfault.com/questions/754351/what-is-a-correct-ways-to-allow-login-to-an-iis-site-through-a-reverse-proxy/755659#755659
Basically, when I set up my reverse proxy, it works fine on pages without logins through iis, but if I have a site with iis login (the popup login similar to sharepoint's login), it just continuously asks for the login. There's no failed login attempt in the logs. I have all error logs listed in the serverfault question. Any help is appreciated. If I get a solution on serverfault, I will post the full question, and answer here.