Three different checks, three different questions
An SSL check, a DNS lookup, and a WHOIS lookup each answer a different question about a website, and confusing them is a common source of misdiagnosed “is this site safe?” concerns.
SSL/TLS certificate check
This tells you whether a website’s connection is encrypted and whether its certificate is currently valid, issued by a trusted authority, and matches the domain being visited. A valid certificate confirms the connection is encrypted and the certificate matches the domain — it does not, by itself, guarantee the site’s content or operator is trustworthy.
DNS lookup
DNS (Domain Name System) translates a human-readable domain name into the numeric IP address that computers use to actually connect. A DNS lookup shows you which records (like A, MX, or CNAME records) a domain currently publishes — useful for diagnosing whether a domain is pointing where it’s supposed to, or whether email/website changes have propagated yet.
WHOIS lookup
WHOIS shows registration information about a domain name itself — such as the registrar, registration and expiry dates, and (where not redacted by privacy protection) registrant details. It’s useful for checking how old a domain is or when it’s due to expire, though many registrants now use privacy services that hide most personal details.
Using all three together
None of these three checks alone proves a website is legitimate or safe. Together, they give useful signals: a very recently registered domain (WHOIS), with no valid certificate (SSL), and DNS records that don’t match its claimed identity, is a combination worth treating with caution.