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In typical operation (for a network that supports a Public Key certificate infrastructure), the Microsoft L2TP/IPSec virtual private network (VPN) client connects without explicit configuration. However, if your VPN network requires that you use a preshared key instead of a certificate for authenticating the client computer on the VPN server, you can use the configuration utility. Your network administrator must give you the value for the preshared key.
Click Start, point to Programs, point to Microsoft IPSec VPN, and then click Microsoft IPSec VPN Configuration. You can then select the option to use a preshared key, and you can type or paste the correct key value in the box.
You can use this utility to select automatic operation (the default), to select a specific certificate, or to select a preshared key. Automatic operation works correctly for most certificate-based authentication. Select a specific certificate if you are instructed to do so by your network administrator.
To Obtain Public Key Certificates
Your network administrator will give you instructions for obtaining the digital certificate that are used to authenticate your computer on the VPN server and the certificate chain that is used to allow your computer to recognize the VPN server. In most cases, the administrator will ask you to use Microsoft Internet Explorer to obtain a certificate.
If your network uses a certification authority (CA) that is based on a Microsoft Windows 2000-based server that is running Certificate Services configured to support Web enrollment, use Internet Explorer to request a certificate from the CA. Use the "http://computername/certsrv" Web address, where computername is the name of the CA computer. Then, follow the instructions on the Web page to request a certificate from the CA.
Or, your administrator may give you a way to obtain a certificate-import package. To install a certificate from such a package, start Internet Explorer, and then click Internet Options on the Tools menu. In the Internet Options dialog box, click the Content tab, and then click Certificates. Click Import, and then follow the instructions in the Certificate Import Wizard.
For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
325035 Limitations and Compatibility Issues of Microsoft L2TP/IPSec VPN
325032 Using the Microsoft L2TP/IPSec VPN Client with Windows 98, Windows Me, and Windows NT 4.0