Event ID 26 — AD CS Online Responder Service

Applies To: Windows Server 2008

The status and functioning of the Microsoft Online Responder service has dependencies on numerous features and components, including the ability to access timely certificate revocation data, the validity of the certification authority (CA) certificate and chain, and overall system response and availability.

Event Details

Resolve

Renew the expired signing certificate for an Online Responder

If a signing certificate for an Online Responder expires, complete the procedure in the "Renew an OCSP Response Signing Certificate" section.

If the certificate renewal process fails, take the following actions:

• Confirm that a CA is accessible.
• Confirm certificate template permissions.
• Confirm that the OCSP Response Signing certificate template is available for use by the CA.
• If renewal of the OCSP Response Signing certificate is successful but the certificate cannot be used by the Online Responder service, use the procedure in the "Confirm access to the OCSP Response Signing certificate by NETWORK SERVICE" section.
• Finally, to minimize the likelihood that this event will recur, you may also want to lengthen the certificate renewal reminder period by using the procedure in the "Modify the certificate renewal reminder period" section.

To perform these procedures, you must have membership in local Administrators, or you must have been delegated the appropriate authority.

Renew an OCSP Response Signing certificate

To renew an OCSP Response Signing certificate:

1. Click Start, type mmc, and then press ENTER.
2. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.
3. On the File menu, click Add/Remove Snap-in, click Certificates, and then click Add.
4. Click Computer account, and click Next.
5. Select the computer hosting the CA, click Finish, and then click OK.
6. In the console tree, double-click Certificates, and then double-click Personal.
7. Right-click Certificates, point to All Tasks, and click Renew Certificate with New Key to start the Certificate Renewal Wizard.
8. Use the wizard to complete the enrollment process. 

Note: The previous procedure assumes that the OCSP Response Signing certificate was configured for manual enrollment and renewal. If the OCSP Response Signing certificate template was configured for autoenrollment and renewal, you can use the same procedure but open the Certificates snap-in for the Online Responder service account rather than the computer account.

Confirm that a CA is accessible

To confirm that a CA is accessible by a client:

1. Open a command prompt window.
2. Type certutil -ping -config<computer\user> and press ENTER.

Note: If you use -config -, the operation is processed by using the default CA. You must specify the computer or user with permission to enroll for certificates from the CA when you use the -config option. Otherwise, the Select Certification Authority dialog box appears and displays a list of all CAs that are available.

Confirm certificate template permissions

To confirm that the the computer on which the Online Responder has been installed has Read and Enroll permissions on the OCSP Response Signing certificate template:

1. On the computer hosting the CA, click Start, type certtmpl.msc, and press ENTER to open the Certificate Templates snap-in.
2. Right-click the OCSP Response Signing certificate template, and then click Properties.
3. Click the Security tab to confirm that the computer hosting the Online Responder has Read and **Enroll **permissions.

Confirm that a certificate template is available to a CA

To publish a certificate template:

1. On the computer hosting the CA, click Start, point to Administrative Tools, and click Certification Authority.
2. In the console tree, right-click Certificate Templates, click New, and then click Certificate Template to Issue.
3. Select the certificate template, and click OK.

Confirm access to the OCSP Response Signing certificate by NETWORK SERVICE

To ensure that the private key for the OCSP Response Signing certificate is accessible to NETWORK SERVICE:

1. Click Start, type mmc, and then press ENTER. 
2. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.
3. On the File menu, click Add/Remove Snap-in, click Certificates, and then click Add.
4. Click Computer account, and click Next.
5. Select the computer hosting the Online Responder, click Finish, and then click OK.
6. In the console tree, double-click Certificates, double-click Personal, and click Certificates.
7. In the details pane, click OCSP Response Signing.
8. On the Actions menu, point to All Tasks, and click Manage Private Keys.
9. Click Add, type NETWORK SERVICE, and then click OK.
10. Ensure that only the Read permission is allowed for NETWORK SERVICE, and then click OK.
11. Restart the Online Responder service.

If the OCSP Response Signing certificate is not valid for signature purposes, enroll for a certificate that includes the id-kp-OCSPSigning Extended Key Usage (EKU), labeled OCSP Signing (1.3.6.1.5.5.7.3.9).

Modify the certificate renewal reminder period

To modify the certificate renewal reminder period:

Caution: Incorrectly editing the registry might severely damage your system. Before making changes to the registry, you should back up any valued data.

1. Click Start, type regedit, and then press ENTER.
2. Go to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\OcspSvc\Responder\.
3. Add a DWORD registry key named ReminderDuration under this root.
4. Enter a value between 1 and 100 to indicate the desired percentage.
5. Stop and restart the Online Responder service to implement the new renewal reminder value.

Note: The reminder duration is an Online Responder-wide property, expressed as a percentage of the certificate lifetime. The default value is 90 percent of the certificate lifetime, but this value can be modified in the registry.

Verify

An Online Responder serves as an intermediary between clients that need to check certificate validity and a certification authority (CA) that issues certificates and certificate revocation lists (CRLs). To verify that the Online Responder service is functioning properly, you need to isolate the Online Responder and client from the CA and any CRL distribution points to confirm that revocation checking continues to take place and that revocation data is originating only from the Online Responder. The best way to confirm this scenario is to complete the following steps that involve the CA, the client, CRL distribution points, and the Online Responder:

• Issue new certificates.
• Revoke a certificate.
• Publish a CRL.
• Remove CRL distribution point extensions from the issuing CA.
• Confirm that client computers can still obtain revocation data.

To perform these procedures, you must be a member of local Administrators on the computer hosting the Online Responder and on the client computer, and you must have Manage CA permissions on the computer hosting the CA, or you must have been delegated the appropriate authority.

Issue new certificates

To issue new certificates:

1. On the computer hosting the CA, click Start, point to Administrative Tools, and then click Certification Authority.

2. Configure several certificate templates to autoenroll certificates for a computer running Windows Vista or Windows XP Professional.

3. When information about the new certificates has been published to Active Directory domain controllers, open a command prompt window on the client computer and enter the following command to start certificate autoenrollment: certutil -pulse.

   Note: It can take up to eight hours for information about new certificates to be replicated to Active Directory domain controllers.

4. On the client computer, use the Certificates snap-in to confirm that the certificates have been issued to the user and to the computer, as appropriate. If they have not been issued, repeat step 2. You can also stop and restart the client computer to initiate certificate autoenrollment.

Revoke a certificate

To revoke a certificate:

1. On the computer hosting the CA, click Start, point to Administrative Tools, and then click Certification Authority.
2. In the console tree, click Issued Certificates, and then select the certificate you want to revoke.
3. On the Action menu, point to All Tasks, and then click Revoke Certificate.
4. Select the reason for revoking the certificate, and click Yes.

Publish a CRL

To publish a CRL:

1. On the computer hosting the CA, clickStart, point to Administrative Tools, and then click Certification Authority.
2. In the console tree, click Revoked Certificates.
3. On the Action menu, point to All Tasks, and then click Publish.

Remove all CRL distribution point extensions from the issuing CA

To remove all CRL distribution point extensions from the issuing CA:

1. On the computer hosting the CA, click Start, point to Administrative Tools, and then click Certification Authority.
2. Select the CA.
3. On the Action menu, click Properties.
4. On the Extensions tab, confirm that Select extension is set to CRL Distribution Point (CDP).
5. Click any CRL distribution points that are listed, click Remove, and click OK.
6. Stop and restart the CA.
7. Configure a new certificate template, and complete autoenrollment again.

Confirm that client computers can obtain revocation data

To confirm that client computers can obtain revocation data:

1. Click Start, type mmc, and then press ENTER.

2. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.

3. On the File menu, click Add/Remove Snap-in, click Certificates, and then click Add.

4. Select the user or computer account to whom the certificate was issued, click Finish, and then click OK.

5. Open the Personal Certificates store, right-click the most recently issued certificate, point to All Tasks, and then click Export to start the Certificate Export Wizard. Export the certificate to a .cer* *file.

6. Open a command prompt window.

7. Type **certutil -url<exportedcert.cer> **and press ENTER.

   Exportedcert.cer is the file name of the certificate that was exported in the previous step.

8. In the Verify and Retrieve dialog box that appears, click From CDP and From OCSP, and confirm that the revocation data is retrieved from the Online Responder and not from a CRL distribution point.

Related Management Information

AD CS Online Responder Service

Active Directory Certificate Services