The Microsoft Challenge Handshake Authentication Protocolversion 1 (MS-CHAP v1) has been deprecated in Windows Vista. This article discusses this change and provides methods to work around it.
In Windows Vista, Microsoft has removed MS-CHAP v1 from the list of authentication protocols for dial-up connections, for broadband (PPPoE) connections, and for virtual private network (VPN) connections. This change has been made because MS-CHAP version 2 (MS-CHAP v2) provides better security than the following protocols do:
The Challenge Handshake Authentication Protocol (CHAP)
Note CHAP provides an equivalent level of security to MS-CHAP.
The Password Authentication Protocol(PAP)
Note PAP is less secure than MS-CHAP.
Microsoft Windows 2000 and later operating systems support MS-CHAP v2, CHAP and PAP. By default, both CHAP and MS-CHAP v2 are enabled for dial-up and PPPoE connections in Windows Vista.
If you used the Set up a connection or network wizard in Windows Vista to create a network connection, you can use the Network Sharing Center to enable or disable PAP, CHAP and MS-CHAP v2. To do this, follow these steps:
Open the Network Sharing Center. To do this, click Start, type network sharing center in the Start Search box, and then click Network Sharing Center in the Programs list.
Click Manage network connections.
In the Network Connections window, right-click the name of the connection that you want to change, and then click Properties.
In the User Account Control dialog box, click Continue.
In the Connection Properties dialog box, click to select the Security tab, click Advanced (Custom Settings), and then click Settings.
In the Advanced Security Settings dialog box, click to either enable or disable the options for PAP, CHAP and MS-CHAP v2, and then click OK.
If you used the Connection Manager Administration Kit in Windows Vista to create a network connection, you can edit the .cms file for the connection to enable or disable PAP, CHAP and MS-CHAP v2. To do this, follow these steps:
Click Start, type notepad in the Start Search box, and then click Notepad in the Programs list.
In the File menu, click Open.
If the connection can be used by all users of the computer, type the following text in the File name box, and then click Open: