[RP-PPPoE] pptp pass thru .

[ratheesh k]

A linux machine ( 2.6.18 kernel ) has two interfaces eth1 ( wan ) and
eth0 ( lan ) , act as a  gateway machine for my home network .
Gateway machine has following iptables rules

iptables -A INPUT -m stat --state ESTABLISHED, RELATED -j ACCEPT
iptables -A INPUT -i eth1 -j DROP
iptables -A INPUT -i eth0 -j ACCEPT

iptables -A FORWARD  -m stat --state ESTABLISHED, RELATED -j ACCEPT
iptables -A  FORWARD  -i eth1  -o eth0 -j DROP
iptables -A FORWARD   -i eth0  -o eth1 -j ACCEPT

This makes router to accept all packets coming from lan side and drop
packets coming from wan ,except established packet .

I dont have any connection tracking module / ALGs loaded in my linux
router box . But still i can establish pptp connection from a client
linux machine connected to eth0 of gateway machine .

I can see GRE packet comiing from wan side get routed in GATEWAY
machine to correct client machine using wireshark .

any hint is really appreciated ...

-Ratheesh.