The directory is configured to require LDAP server signature 1. The LDAP signature requirement for using a group policy server is set to 1. Click Start, click Run, type mmc.exe, and then click OK. 2. Put the file in the menu. Click Add/Remove Snap-in. In the Add or Remove Snap-in dialog box, click Group Policy Management Editor. Click Add. 4. In the Select Group Policy Object dialog box, click Browse. 5. In the Browse Group Policy Objects dialog box, click the default domain policy, domain, ou, and linked group policy objects, and then click OK. 6. Click Finish. 7. Click OK. 8. Default Domain Controller Policy Computer Configuration Policy Windows Settings. Set the local policy securely, and then click Security Options. Right-click Domain Controller: LDAP Server Signing Requirements, and then click Properties. 10. Enable defining this policy setting in the "Domain Controller: LDAP Server Signature Requirements Properties" dialog box, click the drop-down list to select the policy setting that needs to be signed in this definition, and then click OK. 1 1. Click Yes to confirm the settings change dialog box. Second, the setting of the LDAP signature requirement for the client is 1. Click Start, click Run, type mmc.exe, and then click OK. 2. Put the file in the menu, and then click Add/Remove Snap-in. In the Add or Remove Snap-in dialog box, click Group Policy Object Editor, and then click Add. 4. Click Finish. 5. Click OK. 6. Local computer policies Computer configuration policies Windows settings. Security Settings Local Policy, and then click Security Options. Right-click Network Security: LDAP Client Signature Requirements, and then click Properties. 8. Click in the Network Security: LDAP Client Signature Requirements Properties dialog box, select the required signature from the drop-down list, and then click OK. 9. Click Yes to confirm the settings change dialog box.