Installing the Certificate is the last step in getting an SSL Certificate. If required, read about the complete procedure.
Starting from April 7, 2026, Actalis will begin the transition to a new PKI infrastructure for SSL Server certificates.
During this migration phase, the certification chain of SSL certificates will be progressively updated and may include new intermediate certificates and a cross-certificate, necessary to ensure compatibility with browsers and operating systems that do not yet recognize the new Root CAs.
When you install or update an SSL certificate, always make sure to install the entire certification chain provided with the certificate (server certificate + intermediate CA + any cross-certificate).
Where to find the files required for installation
When you install your SSL Certificate, use the file provided in the Certificate issue confirmation email or go to the company website and sign in to your Customer Area. Follow the guide to recover files from the Customer Area.
Normally, there are 2 files:
- one with a .p7b extension containing the SSL Certificate issued and the certification chain;
- one with a .crt extension containing just the SSL Certificate issued.
In some cases, the intermediate CA and the cross-certificate may be provided separately together with the SSL certificate.
Make sure to install all the certificates in the chain provided with the certificate.
- The certification chain of Actalis SSL certificates may include:
- the server certificate;
- the intermediate CA certificate;
- the cross-certificate (used during the transition to the new PKI).
The intermediate CA makes sure that the SSL Certificate issued is considered reliable by the browser.
During the transition phase to the new PKI, the certification chain may also include a cross-certificate.
The cross-certificate links the new Actalis Root CA to the previous Root already present in browsers and operating systems, thus ensuring the correct validation of the SSL certificate.
How to convert a Certificate file to a different format
If you want to convert the file into a different format, you can use:
- an online conversion software. For example, you can use this tool to convert the file to another format;
- OpenSSL from your server/hosting and convert using the command line. More information can be found online.
Once you have converted the file, merge it with the private key file.
Which file to use during installation
During installation, you can use the Certificate in either format, depending on the operating system of the server on which you want to install the SSL Certificate.
For further details, see the guide below.
Certification chain
When installing the SSL certificate, make sure that the certification chain is complete.
The correct configuration must include:
- server certificate;
- intermediate CA certificate;
- cross-certificate (if provided).
The Root CA must not be installed on the server because it is already present in the browsers and operating systems of clients.
How to install an SSL Certificate on an Apache server
Follow the guide to:
How to install an SSL Certificate on a Windows server
How to install an SSL Certificate on a Plesk server
Follow the guide to install an SSL Certificate on Plesk.
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