VPN Windows 7 GRE Firewall & Event Viewer


  • Hi,

    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


    Additional Info:

    1. VPN server and Client are running on Win7 Ultimate version
    2. Have tested with Linksys Router with GRE Passthrough turned On and got the same error (806)
    3. Successful VPN connecting with other laptop in the same LAN.
    4. Error found in Event Viewer is as below:
    • ERROR 20209

    A connection between the VPN server and the VPN client 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.

    Application Information:

    Process ID: 4

    Application Name: System

    Network Information:

    Direction: Inbound

    Source Address: [VPN Server IP]

    Source Port: 1723

    Destination Address: [My DDNS IP]

    Destination Port: 3817

    Protocol:         6

    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????


    Monday, January 30, 2012 11:45 AM

All replies

  • more info...

             7. I have tried disabling Firewall but still got the same result (for VPN - error 806, pptpping command - see 6.)


    Please help...

    Tuesday, January 31, 2012 4:40 PM
  • Hello,

    Still waiting for help.. Could you advise me if I should post it under different topics or any information I need to supply?


    Sunday, February 05, 2012 3:27 AM