I am a software development consultant, and I have a client who is running a PPTP VPN on Windows Server 2008 R2, which I was previously able to connect to via my Hp laptop running Windows 7 Ultimate x64. Now, when I try to connect, I get stuck on "Verifying user name and password", which eventually errors out with: "Disconnected.
Error 806: The VPN connection between your computer and the VPN server could not be completed. The most common cause for this failure is that at least one Internet device (for example, a firewall or a router) between your computer and the VPN server is not configured to allow Generic Routing Encapsulation (GRE) protocol packets. If the problem persists, contact your network administrator or Internet Service Provider."
So, the information I find out on the internet is that basically, as the error message states, GRE needs to be able to traverse between my workstation and the VPN end-point.
I'm fairly sure this is a problem with a configuration on the laptop itself (bad firewall settings, etc), since it used to work, and a Windows 7 professional virtual machine on the same network is able to connect to the VPN successfully.
On the virtual machine that works (Win7 pro), I have windows firewall turned off.
On the machine that doesn't work, I was trying with Windows Firewall set with TCP port 1723 is open both directions, and I've tried GRE enabled/disabled on inbound and outbound, to no effect. It also doesn't work with Windows Firewall turned off.
Machine that DOESN'T work is connected to a 10/100 switch in an upstairs office (I've also tried connecting directly to the wall-jack, skipping this switch, no difference), then to a gigabit switch (servers and fast workstations are connected to this Gb switch) in the server-closet in the basement, which is then connected to a 10/100 switch in the server closet for slower workstations at the punch-panel, and interfacing with the T-Mobile broadband Router/VOIP device, which then connects to the DSL router.
Machine that DOES work is running inside of a VMWare Server instance hosted on Windows 2008, which is plugged into a gigabit switch (servers and fast workstations are connected to this Gb switch) in the server-closet in the basement, which is then connected to a 10/100 switch in the server closet for slower workstations at the punch-panel, and interfacing with the T-Mobile broadband Router/VOIP device, which then connects to the DSL router.
So, the network path is mostly the same, with the exception of the actual computer, and the additional 10/100 switch (which I've removed and still have the problem), and the non-working workstation used to work from this same location, through this same network layout.
Things I've already tried:
1. I've configured the VPN connection to explicitly use PPTP, rather than leaving it as automatic, since I've seen forum posting saying "automatic" causes problems.
2. I've deleted and re-added the VPN connection numerous times, since I've seen postings referring to the need to do so.
3. I've tried turning off windows firewall entirely.
4. I've power-cycled the 10/100 switch in the office, and bypassed it completely.
Any solutions or additional trouble-shooting ideas would be welcome.