setcookie problem - always expires after 24 hours instead 6 hours

[str0ngarm]

Hi there

I have a funny problem with the expiration time of the setcookie function.
I can set the expiration time to any time i want. The cookie always expires after 24 hours.

My PHP Version is:
4.3.6

My code looks following:
setcookie("SET","1",(time() + 21600));

I have tried setting time() + 10 and tested with Mozilla on FreeBSD, Opera on FreeBSD, IE on Mac OS X and Safari on Mac OS X, all Browsers show me the same expiration time (exactly 24 hours later).

The local time on my Server with the code, my FreeBSD Laptop and my G4 are in Sync.

Any ideas what could be wrong?

Thanks for your help
Chris