[development] PHP Sessions behaving strangely

[Khalid B]

Hello Folks.

Hope everyone is enjoying their time off in the holidays.

For the rest of us addicts (I would say most of us), here is a question.

I am developing a module that relies on storing something in the
session. It works fine on my test machine. When I copied the module to
the customer's test machine, I found that sessions behave very
strangely.

Instead of reusing the session id that was assigned on the last
access, it is creating a new session every time the same person from
the same browser and same IP address accesses the site.

The result  is the module does not work, since a new session is
assigned, and the old one is not reused, and the stored values are not
visible.

Looking at session.inc, I found that the function sess_read() is the
one responsible for this. It is passed a $key parameter, which I
assume is assigned by PHP,  and hence  is not a Drupal assigned value.

I checked the session settings parameters in php.ini on the customer's
machine, and found them to be normal.

What can be the cause for this?