IIS 8, 8.5 & 10: SSL Certificate Installation

Overview

This guide walks you through the process of installing an SSL certificate on Microsoft IIS 8, 8.5, and 10. We cover everything from receiving your issued certificate from FairSSL to activating HTTPS on your website.

Note: This guide assumes you generated your Certificate Signing Request (CSR) directly on the server. If you received a PFX file instead (e.g. via the FairSSL CSR service), please refer to our guide on IIS 8-10: PFX Import.

Supported Versions

IIS Version	Windows Server
IIS 8.0	Windows Server 2012
IIS 8.5	Windows Server 2012 R2
IIS 10.0	Windows Server 2016, 2019, 2022, 2025

Prerequisites

• Administrative access to the server
• A CSR generated on this specific server via IIS Manager
• The issued certificate file from FairSSL (usually .crt or .cer)
• The Intermediate Certificate (CA Bundle) provided by FairSSL

Step 1 – Install the Intermediate Certificate

The intermediate certificate allows browsers to verify the full trust chain. This must be installed before the server certificate itself.

1. Save the intermediate certificate as intermediate.cer on your desktop.
2. Press Windows + R, type mmc.exe and press OK.
3. Go to File → Add/Remove Snap-in.
4. Select Certificates, click Add, then choose Computer account → Local computer.
5. Expand Intermediate Certification Authorities → right-click Certificates.
6. Select All Tasks → Import and browse for the intermediate.cer file.
7. Choose Automatically select the certificate store and click Finish.

[Screenshot: MMC → Intermediate Certification Authorities → Import]

Step 2 – Complete the Certificate Request in IIS Manager

1. Press Windows + R, type inetmgr and press OK.
2. Select your server name in the left-hand Connections pane.
3. Double-click Server Certificates in the centre menu.
4. Click Complete Certificate Request in the right-hand Actions pane.
5. Complete the dialogue:
   • File name: Browse to your issued certificate file (.crt or .cer).
   • Friendly name: Enter a descriptive name, e.g. example.com 2026.
   • Certificate store: Select Personal.
6. Click OK. The certificate will now appear in the Server Certificates list.

[Screenshot: IIS Manager → Server Certificates → Complete Certificate Request]

Step 3 – Configure the HTTPS Binding

1. In IIS Manager, expand Sites in the left-hand pane.
2. Select the website that will use the certificate.
3. Click Bindings in the right-hand Actions pane.
4. Click Add and enter the following:
   • Type: https
   • IP address: All Unassigned (or a specific IP)
   • Port: 443
   • Host name: Your domain name (e.g. www.example.com)
   • Require Server Name Indication: Check this box if you host multiple HTTPS sites on the same IP.
   • SSL certificate: Select the certificate you just installed.
5. Click OK and then Close.

[Screenshot: IIS Manager → Site Bindings → Add HTTPS]

Step 4 – Verify the Installation

Open your browser and navigate to https://your-domain.com. Verify that the padlock icon is visible and the certificate details are correct.

We recommend using the FairSSL SSL Scanner to validate the complete certificate chain and your TLS configuration.

Troubleshooting

• "Cannot find the certificate request associated with this certificate file": This usually means the CSR was generated on a different server, or the private key has been deleted. You will need to generate a new CSR and request a certificate reissue.
• Certificate disappears after import: This typically indicates a missing private key. Ensure that both the CSR and the 'Complete Certificate Request' process are performed on the same server.
• Browser displays certificate chain warnings: Ensure the intermediate certificate has been installed correctly as described in Step 1.