在网路连线设定强制设VPN的类型为 PPTP 之后，反而出现 error 609

在网路上找到以下的设定：重新安装 miniports

http://support.microsoft.com/kb/953795

To resolve this issue, uninstall and reinstall the miniports manually. To do so, follow the steps below:

1. Click Start>All Programs>Accessories and click "Command Prompt". (就是DOS命令视窗)

2. In the Command prompt, type the following commands one by one and press Enter after each one.

Netcfg -u MS_L2TP

Netcfg -u MS_PPTP

Netcfg -l %windir%infnetrast.inf -c p -i MS_PPTP

Netcfg -l %windir%infnetrast.inf -c p -i MS_L2TP

如此 错误 609 就解决了

不过后来设定VPN连线时又出现 错误 806，防火牆与PC之间没设好 Generic Routing Encapsulation，再依关键字找 VPN error 806，发现有位Microsoft MVP 的HowToNetworking 网站有以下的解答：

http://www.howtonetworking.com/vpnissues/error806.htm

Error 806: a connection between your computer and the VPN server has been established but the VPN connection cannot be completed. The most common cause for this is that there is at least one internet device between your computer and the VPN server is not configured to allow GRE protocol packets Verify that protocol 47 GRE is allowed on all personal firewall devices or routers. if the problem persists, contact your administrator.

Resolutions:

1) if you have a router/firewall, make sure you open TCP Port 1723, IP Protocol 47 (GRE).

2) make sure you can reach the VPN server by using ping. Sometimes, poor connection can cause this issue too.

3) You may need to updated firmware on a router or firewall.

4) The VPN server may not be able to get IP from DHCP for the VPN client. So, you may want to re-configure VPN host networking settings. For XP pro VPN host, go to the Properties of the VPN>Network, check Specify TCP/IP address and Allow calling computer to specify its own IP address, and uncheck Assign TCP/IP addresses automatically using DHCP.

5) Make sure other secure software blocks your access, for example, if you use Norton secure software, you may need to add the remote client's IP so that the client can access.

6) If your VPN running on a Windows RRAS with NAT enabled, you may want to check the NAT settings.

照着步骤 (1) 设了 TCP 1723 及 47，重开机后还是无法连线.....

后来才发现我的无线网卡不知何时己被设了固定IP (原来是设DHCP) ，重新设回 DHCP自动取得IP，再次连VPN竟然就通了。

为了这个问题花了好几个小时，希望下次有人遇到VPN error 800, VPN error 609 及 VPN 80的问题，看了这篇文章会有帮助。

PS, 我的作业系统：Windows Vista Business on Lenovo X61