iRule to Limit Connections from Source IP to Destination IP

when RULE_INIT {
  set ::max_connections 100
  set static::active_connections 0
}
when HTTP_REQUEST {
    if { not [HTTP::cookie exists ] and $::active_connections > $::max_connections} {
  HTTP::respond 302 Location "" "Connection" "Close" "Cache-Control" "no-cache" "Pragma" "no-cache"
  TCP::close
  } { incr ::active_connections 1
  }
}
when CLIENT_CLOSED {
  incr ::active_connections -1 
}