Updating ASP cookie from ASP.NET (vice versa)

You might encounter a case where updating an ASP (classic/3.0) cookie from ASP.NET code (or vice versa) doesn't work. That is despite updating the cookie value, the old value still remains.

I was working on a having an ASP page communicate some information to an ASP.NET (2.0) page and vice versa and since the information was not that critical/confidential a cookie would do (** for critical information, it is usually done using a common datastore/database or session though that not secure. will not discuss here for now). I expect it to be seamless since they're accessing the same set of cookies after all. However to my surprise it was acting weird.

After a review of some code and I was certain that each of them updates the cookie correctly, it was time to bring up fiddler (or any cookie viewer) and it's when I started getting more clues.

Turns out that the case is actually not "not being updated" but rather a new cookie is created with the same key because of differences in handling cookie paths which must be the same across ASP and ASP.NET for them to talk about the same cookie (using the same name).

Read full article in the following link : Updating ASP cookie from ASP.NET (vice versa)