Automatic PPP disconnection

[crack77@libero.it]

I use a proxy server on a net for Internet on demand   browsing  clients
 on ISDN lines with one modem (shared) on PPP serial line connection.

I need to set active-filter on ppp daemon  together idle option (Debian box with 2.2.17 kernel and CONFIG_FILTER enable, ppp daemon 2.3.11-1.4) because my provider send (packed captured and analyzed with tcpdump and ethereal)

IGMP and PIM packets every 30 seconds to all users connected and  so I have to discard them and setting idle option to adequate interval otherwise my connection is always on !!!.

But PPP daemon don't recognize  active-filter option set in /etc/ppp/options ! I can't solve this problem in ppp daemon  installation because this configuration/compilation option isn't asked to  me.

How can I solve this problem ?

Thank's for service

                                                                                                                    Dan V.