[pptp-server] Why won't this work?!?

[Philip Van Baren]

> When my box is NOT connected to the net, I can VPN in from another box on
> the LAN just fine. As soon as I connect, the box no longer accepts the
> connections. They just time out. The box is BOTH the
> router/gateway AND the
> (hopefully) pptp server. This should work, right? Why doesn't it?

Sounds like a routing problem.  Compare your routing tables before and after
connecting to the internet to see why the internal network gets cut off.

> $IPMASQADM portfw -a -P tcp -L $EXTERNAL_IP 1723 -R $INTERNAL_IP 1723
> ipmasqadm portfw -l
> prot localaddr          rediraddr          lport    rport  pcnt  pref
> TCP  xxx.xxx.xxx.xxx    192.168.5.1        1723     1723    10    10
>
> $IPFWD --masq --syslog $INTERNAL_IP 47 &

If your box is both the router/gateway and the pptp server, there is no need
to do any port forwarding of TCP-1723 or GRE packets.  If your pptp server
actually IS on some machine behind your firewall (other than the firewall
machine itself), then you would need to do forwarding, and should also
install the ip_masq_vpn stuff:

	ftp://ftp.rubyriver.com/pub/jhardin/masquerade/ip_masq_vpn.html

ftp://ftp.rubyriver.com/pub/jhardin/masquerade/VPN-howto/VPN-Masquerade.html