When you don't have a valid authenticated session, the domino server automatically responds with the login form.
The HTTP Status Code of this response however is "200 - OK".
For consuming client code (e.g. in case of using Domino as a REST backend) this means interpreting every response body and checking for a login form, just to know if you're still logged in. This could be made so much easier if Domino would answer with Status Code 401, which is an error code and gets handled as such by most client frameworks.
Christian Kahlau, sirius-net GmbH