VPN outbound problems
First make sure port 1723 is open on the machine you want to connect to
On the router
using tcpdump -i eth0 host WINDOWSIP and not port 22 and not port 80 on the router (where eth0 is the INTERNAL interface) try to make the connection and look at the data.
If you're sending and recieving lots of packets but the final ACKs aren't completing from the remote machine Check if ip masquerading is on /etc/init.d/ipmasq start
If there's outgoing traffic to the remote machine but none coming back make sure ip forwarding is allowed echo "1" > /proc/sys/net/ipv4/ip_forward will allow outbound vpn connections.
If you do that make sure echo "1" > /proc/sys/net/ipv4/conf/all/rp_filter as well