Protecting subdomains is essential for comprehensive website security. SSL.com offers two solutions: Wildcard SSL for simplicity and UCC/SAN Certificates for flexibility. Below is a streamlined overview – for technical workflows, refer to SSL.com’s Knowledgebase.
Wildcard SSL Certificates
Automatic Coverage
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Secures
example.comand all first-level subdomains (e.g.,blog.example.com,shop.example.com) without needing to re-process the certificate when new subdomains are added.
Ideal For
- Sites with dynamic subdomains under one parent domain
- SaaS platforms offering customer-branded portals (e.g.,
clientA.yourservice.com,clientB.yourservice.com) - Organizations launching frequent marketing campaigns with dedicated landing pages (e.g.,
promo1.brand.com,event.brand.com) - Staging or dev environments that require quick provisioning of subdomains
Limitations
- No support for multi-level wildcards (e.g.,
*.*.example.com) - Cannot protect unrelated domains (e.g.,
example.net) - DV Only — Wildcard SSL certificates are available only as Domain Validation; EV wildcards are not permitted by industry rules
UCC/SAN (Multi-Domain) Certificates
Key Steps to Add Subdomains
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Re-process Your Certificate
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Navigate to Orders > Change Domain(s) / Rekey in the SSL.com portal.
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Modify SANs
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Add new hostnames (e.g.,
api.example.com) or wildcard SANs (e.g.,*.example.com). -
Re-use your CSR if organization details stay the same.
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Validation
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Subdomains under previously validated roots (e.g.,
dev.example.com) inherit approval. -
New parent domains (e.g.,
example.net) require fresh validation.
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Wildcard Support Rules
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DV Only — Multi-domain certificates with wildcard SANs are available only as Domain Validation. OV/EV multi-domain certs cannot include any wildcards; every SAN must be an explicit FQDN.
For detailed screenshots and CSR troubleshooting, visit SSL.com’s Multi-Domain Re-processing Guide.
Certificate Comparison
| Feature | Wildcard SSL | UCC/SAN SSL |
|---|---|---|
| Subdomain coverage | Auto-covers all first-level subdomains under one root | Manual SAN listing (explicit FQDNs or *.example.com) |
| Multi-domain support | – | Up to 500 domains & subdomains |
| Wildcard availability | DV Only | DV Only (OV/EV disallow wildcards) |
| Cost model | Fixed price per cert | Base price + per-SAN fee |
When to Choose Which
- Wildcard SSL
Best for dynamic, fast-moving setups like SaaS platforms, marketing teams managing frequent campaigns, and internal environments that spin up many subdomains on a single root domain. - UCC/SAN SSL
Ideal for enterprises securing many distinct domains and subdomains under one certificate—such as international brands with multiple localized sites—and when you need explicit control over each SAN.
Pro Tip – Continuous Peace of Mind
Use SSL.com’s Health Check Monitoring (HCM) service to receive real-time alerts on certificate expirations, misconfigurations, and installation issues before they affect users.
Need Assistance?
- Quick Help: Live chat in the SSL.com portal (bottom-right corner)
- Deep Dive: Email Support@SSL.com for architecture reviews or complex multi-domain setups
- Windows Users: Try SSL.com Manager for streamlined CSR generation and certificate installs on Windows servers
