Last modified: February 16, 2023

Overview

The system runs the /usr/local/cpanel/bin/checkallsslcerts script during the nightly cPanel & WHM update (upcp) process. This script performs the following actions:

• Requests a Sectigo-signed SSL certificate to replace certificates that meet any of the following conditions:
  • It maintains a weak signature algorithm.
  • It has been revoked.
  • It does not have a Subject Alternative Name (SAN) extension.
  • It does not have an Extended Key Usage (EKU) extension with the Server Authentication value.
  • It is self-signed.
  • It is invalid (for example, your server’s hostname must be valid and resolve in DNS).
  • It will expire soon, based on the following criteria:
    • cPanel-provided certificates that expire in less than 25 days.
    • Certificates issued by any other provider that expire in less than 3 days.
• Updates the SSL certificate for all cPanel & WHM services.
  Note:

  • If any of the above is not true, the system installs a self-signed SSL certificate instead.
  • For more information about SSL certificates, read our Generate an SSL Certificate and Signing Request and Manage AutoSSL documentation.

What the script does

When the /usr/local/cpanel/bin/checkallsslcerts script runs, the system performs the following steps:

1. The system creates a Domain Control Validation (DCV) file, which resembles the following example:

   4221C402112E4831C72C2E004614C47C.txt

   Note:

   Systems that use EasyApache 4 store this file in the /var/www/html/.well-known/pki-validation directory.

2. The system performs a DNS lookup for the hostname’s IP address on the root nameservers.
   Note:

   If the hostname returns multiple IP addresses, the system will use the first IP address.

3. The system uses the hostname’s IP address to confirm that it can access the Domain Control Validation (DCV) file.
   • For cPanel & WHM servers, the script uses HTTP validation of the DCV file.
   • For cPanel DNSOnly® servers, the script uses DNS validation against a DNS TXT record.
4. When the local DCV check passes, the system sends a request to the cPanel Store API for the new SSL certificate.
   • If a valid SSL certificate exists and matches the DCV file, the system does not perform any action.
   • If the system must issue a new SSL certificate, the system sends a request to Sectigo.
   • Sectigo validates the DCV file from the following IP addresses:

     1 2 3 4

     178.255.81.12 178.255.81.13 91.199.212.132 199.66.201.132

     Important:

     Sectigo uses these IP addresses to attempt to access the cPanel server. You must allow these IPs in the server firewall. For more information, read our How to Configure Your Firewall for cPanel & WHM Services documentation.

5. The system logs the Sectigo requests for HTTP DCV in the /etc/apache2/logs/access file. It also contains user agent strings that show who accesses the DCV file. These user agent strings resemble the following examples:
   • cPanel user agent strings

     1 2	192.0.2.0 - - [16/Jun/2016:16:16:16 -0500] "GET /4221C402112E4831C72C2E004614C47C.txt HTTP/1.1" 200 53 "-" "Cpanel-HTTP-Client/1.0" 192.0.2.0 - - [16/Jun/2016:16:16:16 -0500] "GET /4221C402112E4831C72C2E004614C47C.txt HTTP/1.1" 200 53 "-" "Cpanel-HTTP-Client/1.0"

   • Sectigo user agent strings

     1 2	199.66.201.132 - - [16/Jun/2016:16:18:46 +0000] "GET /4F571E4CB76F46E37B8118CEA1DB42BA.txt HTTP/1.1" 200 53 "-" "SECTIGO DCV" 199.66.201.132 - - [16/May/2016:16:18:46 +0000] "GET /4F571E4CB76F46E37B8118CEA1DB42BA.txt HTTP/1.1" 200 53 "-" "SECTIGO DCV"

Run the script

To run this script on the command line, use the following format:

/usr/local/cpanel/bin/checkallsslcerts [options]

Options

Use the following options with this script:

The allow-retry options

When the system checks the cPanel Store after an hour, it runs the following command:

/usr/local/cpanel/scripts/try-later --action '/usr/local/cpanel/bin/checkallsslcerts --no-retry' --check '/bin/sh -c exit 1' –delay 60 --max-retries 1 --skip-first

If the system must retry the SSL certificate update process, it adds an entry in the at daemon (atd) job queue. To view, execute, or remove a job from the atd queue, use the /usr/local/cpanel/scripts/try-later script with one of the following options:

Output

If this script detects errors when it runs, it sends an email to the system administrator that contains warnings about those errors.

Disable a cPanel-signed hostname certificate

To disable a cPanel-signed hostname certificate’s installation, run the following command:

touch /var/cpanel/ssl/disable_auto_hostname_certificate

To disable the automatic replacement of all expired service certificates and disable notifications about expired or expiring service certificates, run the following command:

touch /var/cpanel/ssl/disable_service_certificate_management