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 ConnectionWizard (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.
On the Small Business Server 2003-based server, click To Do List in the left pane of the Server Management console.
Under Network Tasks, click Configure Remote Access.
Click Next, click Enable Remote Access, click to select the VPN Access check box, and then click Next.
Type the fully qualified public domain name (FQDN) of your server, click Next, and then click Finish.
When the wizard is completed, click Close.
Start the ISA Management program, and then click Access Policy.
Right-click IP Packet Filters, and then click Properties.
On the General tab, click to select the Enable IP Routing check box.
On the PPTP tab, click to select the PPTP through ISA firewall check box.
For additional information about how to enable PPTP clients to connect through an ISA firewall, click the following article number to view the article in the Microsoft Knowledge Base:
283628 How to enable PPTP clients to connect through an ISA firewall