Monday, April 11, 2005

Enabling "automatic logon" on Windows NT/2000/XP

Sometimes maybe you need some of your servers logon after reboot automatically ...

The following registry hack details the registry keys which control automatic logon:
..
Hive: HKEY_LOCAL_MACHINE
Key: SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Name: AutoAdminLogon
Type: REG_SZ
Value: 1 enable auto logon
Value: 0 disable auto logon


Hive: HKEY_LOCAL_MACHINE
Key: SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Name: DefaultUserName
Type: REG_SZ
Value: account to logon automatically


Hive: HKEY_LOCAL_MACHINE
Key: SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Name: DefaultPassword
Type: REG_SZ
Value: pw for DefaultUserName above
Caution: Password is stored in clear text. Set security permissions on Winlogon subkey to protect the account used.

Hive: HKEY_LOCAL_MACHINE
Key: SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Name: DefaultDomainName
Type: REG_SZ
Value: if domain account, domain name; if local account, server name


Windows 2000 / XP has an additional registry setting to force autologon and ignore bypass attempts. This can be valuable with a kiosk environment:

Hive: HKEY_LOCAL_MACHINE
Key: SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Name: ForceAutoLogon
Type: REG_SZ
Value: 1


The following registry values must not exist: LegalNoticeCaption, LegalNoticeText. These values force a person logging into a PC to acknowledge having read the notice. If these values exist, the legal notice dialog hangs until someone hits enter. Don't just null out the values. Delete them.

The value DontDisplayLastUserName determines whether the logon dialog box displays the username of the last user that logged onto the PC. The value does not exist by default. If it exists, you must set it to 0 or the value of DefaultUser will be wiped and autologon will fail.

Finally, the value RunLogonScriptSync determines whether a logon script will run synchronously or asynchronously. It should not effect this process but there have been reports that setting the value=1, that is, sychronous, is more stable.

Whether you use the Autologon utility or the registry approach, there are times when you must logon as another user or need the logon dialog to appear. Hold down the shift key until during boot until the logon dialog appears. For the control freaks, even the shift override can be blocked (also see ForceAutoLogon above) :

Hive: HKEY_LOCAL_MACHINE
Key: SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Name: IgnoreShiftOverride
Type: REG_SZ
Value: 1


If you want to enable autologon for a certain number of times, follow the above instructins and use the following Windows NT / W2K / XP registry hack:

Hive: HKEY_LOCAL_MACHINE
Key: SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Name: AutoLogonCount
Type: REG_SZ
Value: # autologons you want to allow

No comments:

There was an error in this gadget