I was working on integrating the Auth component of CakePHP with a legacy database and while it was working on Firefox, I noticed that it wasn’t on IE6, the customer target platform. By looking at the database log, I was sure that the authentication process was ok but Internet Explorer seemed to have a problem with the session cookie, disconnecting as soon as the redirect after authentication was done.
I quickly suspected a problem with cookie, and talking about cookie, I thought to a domain name issue. After googling a bit, I found that underscore « _ » in a host name was an invalid character. So if you need to define local host names while developing, use only [a-z0-9] and « - » to avoid troubles.