How to Replace SSL Certificate in IIS: A Step-by-Step Guide for Web Administrators

Why Proper SSL Certificate Replacement Matters

According to Cybersecurity Ventures, 85% of website outages caused by certificate errors could be prevented through proper renewal workflows. Replacing SSL certificates in IIS requires precision to avoid service disruptions while maintaining HTTPS security.

Preparing for IIS Certificate Replacement

1. Obtain Your New SSL Certificate

• Purchase from a CA/B Forum validated provider like SSLRepo
• Ensure your CSR matches the server’s FQDN (e.g., www.yourdomain.com)
• Verify certificate chain includes intermediate CA certificates

2. Backup Current Configuration

# Export existing certificate
Export-IISCertificate -Name "Current_SSL" -Path C:\SSL_Backup\current.pfx -Password $secureString

Always test backups before proceeding – Microsoft Security Advisory

Step-by-Step IIS Certificate Replacement Process

Step 1: Open IIS Manager

1. Press Win+R, type inetmgr
2. Navigate to Server Certificates under server node

Step 2: Install New Certificate

1. Right-click Server Certificates
2. Select Import and browse to your .pfx file
3. Enter certificate password
4. Check “Allow this certificate to be exported”

Step 3: Bind New Certificate to Website

1. Expand Sites > Select your website
2. Click Bindings in right panel
3. Edit existing HTTPS binding:

• SSL certificate: Select new certificate
• Verify host name matches SAN entries

1. Keep old binding temporarily for rollback

Step 4: Verify Installation

openssl s_client -connect yourdomain.com:443 -servername yourdomain.com

Check for:

• Correct certificate expiration date
• Full chain trust (root → intermediate → server)
• TLS 1.2/1.3 protocol support

Common Replacement Errors & Solutions

Error	Solution
ERR_SSL_VERSION_OR_CIPHER_MISMATCH	Update cipher suite order
Certificate trust chain broken	Reinstall intermediate certificates
SNI mismatch	Verify host header in binding

Post-Replacement Best Practices

1. Monitor certificate status using SSL Labs API
2. Set calendar reminders 45 days before expiration
3. Maintain parallel certificates during transitions
4. Audit certificate usage quarterly

Industry Statistics

• Average enterprise manages 22,000 certificates (Venafi 2023 Report)
• 74% of organizations experienced certificate-related outages in 2023 (Ponemon Institute)
• TLS 1.3 adoption reached 68% in Q2 2024 (Google Transparency Report)

“Certificate lifecycle automation reduces configuration errors by 92%” – Microsoft Security Practice Guidelines 2024