Ubuntu – Can’t reach hosts in same network as server via pptpd on ubuntu 10.4

It's not entirely clear to me how you got PPTP working to the Windows XP server when you have forwarded all port 1723 traffic to the Debian Squeeze server. You likely can only "VPN" to the WinXP server from within your local LAN, which seems to be of limited usefulness.

Regardless, PPTP requires not only TCP port 1723 traffic, but also GRE protocol. Is your router capable of handling GRE tunnels correctly? If it's an ordinary consumer-grade router, then I suspect not. And even if it is, GRE is esoteric enough that finding help may be difficult.

In your case I recommend trying a VPN solution that uses only TCP and/or UDP transports, since those protocols are ubiquitous and well-known. OpenVPN is one such VPN solution, and it is available for all the major OSes (Win, Mac, Linux, *BSD).

Depending on what you're trying to accomplish, another possibility is to run sshd on the Debian server, e.g.:

apt-get install openssh-server

All the major OSes have free ssh clients capable of creating tunnels over an ssh connection.

you're doing it wrong.

1st - use layer 3 connections instead of layer 2 for vpn. Saves traffic.

2nd - use brouting to get the trick done with proxy-arp and assing ip addresses from the local subnet to the vpn clients - so they just appear as they're local

3rd - or use routing and set the route to the clients in the 10.22.8/24 subnet on all systems in the 192.168.1.0/network OR just use the vpn system as the default gateway to avoid routing problems...

Using brouting:

• Enable proxy_arp on the linux router: echo 1 > /proc/sys/net/ipv4/conf/proxy_arp
• Add the route of the subnet to eth0 if not happened automagically

• Add the route of a subnet of the local subnet to the tun device from openvpn.

  Lets say we're going to use the last 16 IP-addresses for the hosts on the vpn (192.168.1.240 - 192.168.1.255) that means we have a 28 bits subnet 192.168.1.240/28. Create the tun device static (openvpn --mktun) and then add the route for the vpn subnet to the device ip route add 192.168.1.240/28 dev tun0

After this, and after enabling ip forwarding and proxy arp the linux system will "broute" all requests from the local clients to the clients at the vpn end and vice versa.

And you have an layer 3 vpn (faster, less traffic) with layer 2 connectivity and fully transparent access to all systems.

Filtering and everything else can be done via iptables.

KR,

Gromit