I have been trying to set up VPN between 2 computers and get error 806 (about GRE blocking). I am pretty sure that I went through all the required configurations, including:
- Enable Inbound firewall setting for PPTP (1723) and GRE protocol 47
- setting "allow the edge traversal" for GRE protocol (in Advanced tab)
- Disabling antivirus (panda) to ensure that it isn't blocking VPN passthrough
- confirming with SMC support guy that the router (model SMC790WBRA2) supports built-in GRE passthrough. No further configuration required.
- Routing and Remote Access Service
- Enable IPSec and Windows Firewall Audit-Events (According to suggestion from http://social.technet.microsoft.com/Forums/en-US/windowsserver2008r2networking/thread/297976ae-1aae-4948-b7a5-2f6a466e089c/)
- VPN server and Client are running on Win7 Ultimate version
- Have tested with Linksys Router with GRE Passthrough turned On and got the same error (806)
- Successful VPN connecting with other laptop in the same LAN.
- Error found in Event Viewer is as below:
- ERROR 20209
A connection between the VPN server and the VPN client 188.8.131.52 has been established, but the VPN connection cannot be completed. The most common cause for this is that a firewall or router between the VPN server and the VPN client is not configured to allow Generic Routing Encapsulation (GRE) packets (protocol 47).
5. From the Firewall audit log, I could see only log saying about Port 1723, couldn't see any related to Protocol 47.
The Windows Filtering Platform has permitted a connection.
Process ID: 4
Application Name: System
Source Address: [VPN Server IP]
Source Port: 1723
Destination Address: [My DDNS IP]
Destination Port: 3817
6. Run PPTP command: pptpsrv.exe and pptpcInt.exe
Output: Client side - connectivity test to TCP Port 1713 was successful, creating a socket to test GRE traffic and sent out.
Server side - Stopping at "Listening on PROTOCOL 47 for incoming GRE packets...."
Can someone help me figure out where GRE get blocked please????