SAN Certificate
SecuritySAN Certificate is an SSL/TLS certificate that secures multiple hostnames within a single certificate by listing them in the Subject Alternative Name (SAN) field. It can cover different domains, subdomains, or services, reducing the need to manage separate certificates. SAN certificates are commonly used for multi-site hosting, load-balanced applications, and environments where many endpoints must be encrypted consistently.
How It Works
A SAN certificate contains one primary Common Name (CN) plus an extension called Subject Alternative Name that enumerates additional DNS names (and sometimes IP addresses) the certificate should be valid for. During the TLS handshake, a browser or client checks whether the hostname it connected to matches either the CN or one of the SAN entries. If it matches and the certificate chain is trusted, the connection proceeds as HTTPS without hostname warnings.
In hosting, SAN certificates are installed on the web server or reverse proxy (for example, Nginx, Apache, HAProxy) that terminates TLS. One certificate can then be reused across multiple virtual hosts, containers, or backend services as long as every public hostname is included in the SAN list. When you add or remove hostnames, you typically need to reissue the certificate so the SAN field reflects the current set of names, then redeploy it everywhere it is used.
Why It Matters for Web Hosting
SAN certificates affect both cost and operational complexity when comparing hosting plans. If you run several sites or services, a single SAN certificate can simplify renewals, reduce configuration drift, and make it easier to standardize HTTPS across environments. When evaluating a host, look for support for multi-domain SSL, automated issuance and renewal, and straightforward deployment to multiple vhosts, load balancers, or control panels like cPanel.
Common Use Cases
- Securing multiple websites on one server (for example, example.com, www.example.com, blog.example.com)
- Covering several distinct domains managed by the same organization
- HTTPS for microservices or APIs exposed under different hostnames
- TLS termination on a load balancer serving many hostnames
- Staging and production endpoints that need consistent certificate management
SAN Certificate vs Wildcard Certificate
A SAN certificate lists specific hostnames explicitly, which is ideal when you know exactly which domains and subdomains must be covered and you want tight control. A wildcard certificate covers many subdomains under a single domain pattern (for example, *.example.com) but does not automatically cover other base domains. In practice, SAN is better for multi-domain setups, while wildcard is often better for many changing subdomains within one domain; some certificates can combine both approaches by including wildcard entries as SANs.