how i can set session time out to some desired time without cookies

[dervaish]

hi!
i am using php 4.0.4,window 9x platform iis,
i want that on my site if a user doesnt interact for 30 miniutes,
his sesssion should expire
is there any way to do this without changing php.ini
i have used ini_set() to change session.cache_expire and session.gc_maxlifetime but its not working
and also my version doesnt support session_cache_expire()

thanking in advance for help

                                dervaish

[Weedpacket]

What about session.gc_probability?

Note that these need to be set before session_start() is called.