Searchlab SSL, DNS and WHOIS: The Three Layers Every Site Owner Should Know
SSL keeps user data encrypted. DNS routes visitors to your server. WHOIS is the public record of who owns the domain. Misconfigure any of them and you get downtime, security warnings, or worse, a domain you can't recover.
SSL: more than just the padlock
An SSL (TLS) certificate proves to browsers that your server is who it claims to be, AND encrypts everything in transit. Modern browsers mark sites without one as "Not Secure", a huge trust killer.
- Valid until? Most certificates last 90 days (Let's Encrypt) or 1 year. Set up auto-renewal, expired certs break your site immediately.
- Issuer? Let's Encrypt is free and trusted. Paid CAs offer extended validation (EV), but Chrome stopped showing EV badges in 2019, less value than before.
- Algorithm? SHA-256 is the minimum. Anything older is rejected by modern browsers.
DNS records you should understand
- A: maps your domain to an IPv4 address. The most fundamental record.
- AAAA: same as A but for IPv6.
- CNAME: points one hostname to another (e.g. www -> root).
- MX: directs incoming email to your mail server.
- TXT: stores arbitrary text. Used for SPF, DKIM, DMARC, and domain verification.
- NS: lists which servers are authoritative for your domain.
WHOIS: what it shows and what it hides
WHOIS is the public record of who owns a domain, when it was registered, when it expires, and which registrar manages it. Since GDPR, most personal details are redacted by default, but registrar, dates, and name servers are still public.
WHOIS data is useful for: checking domain age (older = generally more trusted), spotting expiring competitor domains, and reaching out to a domain owner.