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Why SSL Certificate Checking Matters for Website Security

SSL (Secure Sockets Layer) and its modern successor TLS (Transport Layer Security) are cryptographic protocols that encrypt the data exchanged between a browser and a web server. When a website has a valid SSL certificate, the connection uses HTTPS, and any data transmitted — including passwords, payment details, form submissions, and cookies — is encrypted and cannot be intercepted by attackers. Browsers clearly indicate HTTPS connections with a padlock icon in the address bar, and they display security warnings for sites with expired or invalid certificates.

SSL certificates are issued by Certificate Authorities (CAs) — trusted organizations that verify the identity of the certificate requester. Let's Encrypt provides free automated certificates valid for 90 days, while paid CAs like DigiCert and Sectigo offer certificates valid for up to 398 days with additional validation levels. Domain Validation (DV) certificates only verify domain ownership, Organization Validation (OV) verifies the organization's legal existence, and Extended Validation (EV) requires the most thorough background check. Most websites use DV certificates, while e-commerce and banking sites typically use OV or EV for increased user trust.

Checking SSL certificate expiry is one of the most important maintenance tasks for any website owner. An expired certificate causes browsers to block access to your site and display full-page security warnings — effectively taking your site offline for most visitors. Google Chrome, Safari, and Firefox all enforce strict certificate validation and will refuse to load pages with expired, self-signed, or mismatched certificates. The IPLocatorTools SSL Checker reads the live certificate directly from the server and displays the issuer, issue and expiry dates, days remaining, subject alternative names (SANs), and protocol version.

Subject Alternative Names (SANs) are particularly important because they define which domain names a single certificate covers. A certificate for example.com might also cover www.example.com, api.example.com, and mail.example.com as SAN entries. Missing SAN entries cause mismatch errors for subdomains. Wildcard certificates prefixed with * cover unlimited subdomains of a single registered domain. The SSL Checker displays all SAN entries so you can verify that every subdomain your site uses is covered by the certificate.

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◉ Security Tool

SSL Certificate Checker

Verify any domain's SSL/TLS certificate — issuer, expiry date, days remaining, and validity. Reads the live certificate directly.

SSL Certificate Basics

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What is SSL?

SSL/TLS encrypts data between browser and server. HTTPS requires a valid certificate from a trusted Certificate Authority.

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Certificate Expiry

Certs expire after 90 days (Let's Encrypt) to 1 year. Expired certs cause browser security warnings — monitor expiry dates.

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Certificate Authority

CAs like Let's Encrypt, DigiCert, and Cloudflare sign certificates. Browsers trust certificates from recognised CAs.

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SANs & Wildcards

One cert can cover multiple domains via SANs. A wildcard cert (*.example.com) covers all subdomains automatically.

SSL Certificate — Frequently Asked Questions

Enter the domain at IPLocatorTools SSL Checker and click Check SSL. The tool shows whether the certificate is valid, who issued it, and when it expires.

SSL certificates have an expiry date — typically 90 days to 1 year. When a certificate expires, browsers show a security warning and visitors cannot connect securely. Most hosting providers auto-renew certificates, but you should monitor expiry dates for critical domains.

The SSL certificate issuer (Certificate Authority or CA) is the organization that verified and signed the certificate. Common issuers include Let's Encrypt (free, automated), DigiCert, Sectigo, and Cloudflare. Certificates from trusted CAs are accepted by all major browsers.

SANs (Subject Alternative Names) are additional domain names or subdomains covered by the same certificate. For example, a certificate for example.com might also cover www.example.com and api.example.com as SANs. Wildcard certificates cover all subdomains of a domain.

SSL (Secure Sockets Layer) is the older protocol, now deprecated. TLS (Transport Layer Security) is the modern replacement. The term SSL is still commonly used but all modern secure connections use TLS 1.2 or TLS 1.3. When people say SSL certificate they mean a certificate used for TLS encryption.