PPTP Forwarding

[ryoku1023]

Ok, I'm very "green" with Linux but have decided to go with Debian because I love all the tools it comes with. Recentely I installed one as a router behind a Cisco Pix. I have everything setup to forward all port 1723 and protocol 47 traffic to my Windows server for a vpn connection. Below is my script that runs at startup, but when we try and connect, it just hangs at "verifying username and password." Using tcpdump I am getting nothing in the logs for the gre protocol forward.

iptables -t nat -A PREROUTING -p tcp -i eth0 --dport 1723 -j DNAT --to 192.168.$
iptables -A PREROUTING -t nat -p gre -i eth0 -j DNAT --to-destination 192.168.4$

iptables -A eth1-in --protocol 47 -i eth1 -j ACCEPT
iptables -t nat -A PREROUTING -i eth1 --protocol 47 -j DNAT --to 192.168.40.249

I have done some research and found tools like ipfwd and pptpconfig, but it's all really confusing to me. Everything is done at a command prompt. Would it be easier to go through KDE instead? Any help would be amazing. Thanks in advance.

[ashwin_think]

Hey,

Tryout these rules, -

iptables -t nat -I PREROUTING -p 47 -s $SOURCE-IP -d $PUBLIC-IP-OF-GATEWAY -j DNAT --to $INTERNAL-VPN-SERVER
iptables -I FORWARD -p 47 -d $INTERNAL-VPN-SERVER -j ACCEPT
iptables -t nat -I POSTROUTING -p 47 -d $INTERNAL-VPN-SERVER -j MASQUERADE

What those three rules do is do a port forward for protocol 47. Note that you do not need the -s $SOURCE-IP section, it can be deleted.

iptables -t nat -I PREROUTING -p tcp -d $PUBLIC-IP-OF-GATEWAY --dport 1723 -j DNAT --to $INTERNAL-VPN-SERVER:1723
iptables -I FORWARD -p tcp -d $INTERNAL-VPN-SERVER --dport 1723 -j ACCEPT
iptables -t nat -I POSTROUTING -p tcp -d $INTERNAL-VPN-SERVER --dport 1723 -j MASQUERADE

Those rules port forward port 1723 to the local machine.

iptables -I FORWARD -p 47 -j ACCEPT
iptables -t nat -I POSTROUTING -p 47 -j MASQUERADE
iptables -I FORWARD -p tcp -s $INTERNAL-VPN-SERVER -j ACCEPT
iptables -t nat -I POSTROUTING -p tcp -s $INTERNAL-VPN-SERVER -j MASQUERADE


Regards,
Ashwin.