This is an iptables module and it can match Caller-Station-Id attribute from PDP Create Context request. It also implements whitelisting by Station-Id ranges. This is open source and released under the terms of the GNU General Public License v2

pdp match options for PDP Create Context requests:
—pdp-any Match any request
—pdp-reserved Match hardcoded list of station ids
—pdp-station-id num Match particular Calling-Station-ID

iptables -A INPUT -m pdp —pdp-reserved -j ACCEPT
iptables -A INPUT -m pdp —pdp-station-id 111111111111 -j ACCEPT
iptables -A INPUT -m pdp —pdp-any -j DROP

• You should edit whitelist.c to change harcoded list of Station-Id ranges

For getting help or discussing about pdp, you can join #support on the irc.realisticgroup.com or email to lex@realisticgroup.com.