Article ID: 886621 - View products that this article applies to.
Microsoft Windows Small Business Server 2003-based client computers may not be able to make outgoing Point-to-Point Tunneling Protocol (PPTP) connections, and you may receive the following error message:
Error 800: Unable to establish the VPN connection. The VPN server may be unreachable, or security parameters may not be configured properly for this connection.
This issue occurs because the Configure E-mail and Internet Connection Wizard (sometimes known as CEICW) does not enable PPTP connections through the Microsoft Internet Security and Acceleration (ISA) firewall.
To resolve this issue, enable PPTP through the ISA firewall by using one of the following methods.
Note Use Method 1 if you want to enable remote access when your client computers connect to your server over the Internet. Use Method 2 if your internal LAN clients must access a remote PPTP VPN Server.
(http://support.microsoft.com/kb/283628/ )How to enable PPTP clients to connect through an ISA firewall