PPTP Server and PPTP clients on a firewalled gateway

["A. Sayler" <asayler@qorvus.net>]

Hi,

If anybody might some insight into this problem I would certainly appreciate it.

I have multiple wireless clients that need access to outside corporate VPN servers through my system.  I also have a PPTP server listening on the local gateway host for other users to connect to our internal network from outside.

I have a 2 NIC system. 

I have an internal interface of WLAN0 and the external interface of ETH0.

I have made sure to load the following modules...
ip_conntrack_proto_gre
ip_conntrack_pptp
ip_nat_pptp
ip_nat_proto_gre

I have added the following commands to the rest of my firewall rules

iptables -I INPUT -p 47 -j ACCEPT
iptables -I INPUT -p tcp --dport 1723 -j ACCEPT

iptables -I OUTPUT -p 47 -j ACCEPT
iptables -I OUTPUT -p tcp --dport 1723 -j ACCEPT

iptables -I FORWARD -p 47 -j ACCEPT
iptables -I FORWARD -p tcp --dport 1723 -j ACCEPT

iptables -I FILTER -p 47 -j ACCEPT
iptables -I FILTER -p tcp --dport 1723 -j ACCEPT

I'm masquerading all connections out.

currently the clients can get out and connect properly but the outside clients trying to connect to our local system via the PPTP server on the gateway box can not get a connection.

I think it has something to do with how I'm routing the connection to the local host but I'm not sure what I need to change. Or is this even possible?

Any thoughts?

Thanks,
Adam