HTTP limit does not reduce sessions

Hi, i used the HTTP session limit on my web, but i can't figure why the total connection of the hhtp does not reduce, but only increased and after few minutes the site can not serve, and i have to remove the irule ?

 

 

rule HTTP_session_limit {

 

when RULE_INIT {

 

set ::total_active_clients 0

 

set ::max_active_clients 100

 

log local0. "rule session_limit initialized: total/max: $::total_active_clients/$::max_active_clients"

 

}

 

when HTTP_REQUEST {

 

; test cookie presence

 

if {[HTTP::cookie exists "ClientID"]} {

 

set need_cookie 0

 

set client_id [HTTP::cookie "ClientID"]

 

; if cookie not present & connection limit not reached, set up client_id

 

} else {

 

if {$::total_active_clients < $::max_active_clients} {

 

set need_cookie 1

 

set client_id [format "%08d" [expr { int(100000000 * rand()) }]]

 

incr ::total_active_clients

 

; otherwise redirect

 

} else {

 

HTTP::redirect "http://sorry.domain.com/"

 

return

 

}

 

}

 

}

 

when HTTP_RESPONSE {

 

; insert cookie if needed

 

if {$need_cookie == 1} {

 

HTTP::cookie insert name "ClientID" value $client_id

 

}

 

}

 

when CLIENT_CLOSED {

 

; decrement current connection counter for this client_id

 

if {$::total_active_clients > 0} {

 

incr ::total_active_clients -1

 

}

 

}

 

}