What’s the difference between *.duckduckgo.com and duckduckgo.com? On the SSL certificate it shows the two at the bottom as valid DNS for DuckDuckGo. I understand the asterisk is a wildcard in code, but before a lot of domains I see the same thing. Can someone briefly answer this question?

1 Answer 1


In computer networking, a wildcard certificate is a public key certificate which can be used with multiple sub-domains of a domain.

A single wildcard certificate for https://*.example.com will secure all these subdomains on the https://*.example.com domain:


Instead of getting separate certificates for subdomains, you can use a single certificate for all main domains and subdomains and reduce cost and complexity.

Source: Wikipedia Wildcard certificate

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