A padlock icon showing correctly in your own browser is a start, but it's not a complete verification — several categories of problem can exist on a "working" certificate that a casual glance wouldn't catch, and each is worth checking explicitly before considering an installation genuinely complete.
The checklist
1. A full SSL scan, not just a browser glance
An SSL scan tool (like Qualys SSL Labs' SSL Server Test) checks far more than a browser padlock does — chain completeness, supported protocol versions, cipher suite strength, and known vulnerability exposure — surfacing configuration issues invisible to a normal browsing experience, since browsers are generally lenient about accepting a working-but-suboptimal configuration without warning the visitor.
2. Testing beyond your own browser
Your own regular browser caches certificates and redirects aggressively, and may have already cached a working state from before a configuration change. Test in a private/incognito window, and ideally on a genuinely separate device (a phone on mobile data, not the same Wi-Fi network) — mobile clients and non-desktop-browser tools are less forgiving about incomplete certificate chains than some desktop browsers that cache intermediates.
3. Verifying the redirect is actually a 301
curl -I http://yourdomain.comConfirm the response is a 301 (permanent) rather than a 302 (temporary) — a detail invisible in normal browsing but meaningful for search engine ranking signal transfer, and a common misconfiguration when a redirect rule was written or copied incorrectly.
4. Checking for mixed content systematically
Open browser DevTools' Console tab on your homepage and a few representative inner pages (not just the homepage — mixed content often lives in specific templates or older content, not universally across the site), looking specifically for mixed content warnings that identify the exact offending resource URL.
5. Confirming the certificate chain is genuinely complete
openssl s_client -connect yourdomain.com:443 -showcertsThis shows exactly what your server sends, including intermediates — the definitive way to confirm chain completeness, rather than inferring it from a browser padlock that might be silently filling a gap using its own cached intermediate certificate store.
6. Checking from a genuinely different network perspective
Online SSL checker tools query your server from their own infrastructure, independent of your local network's DNS cache or any local proxy/VPN that might be affecting what you personally see — useful as an independent confirmation that what you're testing locally matches what a random visitor elsewhere would actually experience.
Building this into a repeatable habit
For any domain that matters, this checklist is worth running not just once after initial installation, but again after any renewal, server migration, or infrastructure change (a new CDN, a new load balancer) — each of those is a plausible point where a previously correct configuration can silently regress, and the cost of running through this list again is small compared to discovering a gap from an actual visitor's bad experience instead.
What a comprehensive testing checklist looks like assembled from every check in this guide
A complete checklist covers: SSL scan tool grade, chain completeness via OpenSSL, redirect status code via curl, mixed content check via DevTools, and OCSP stapling status — five independent checks together covering the categories of failure a single browser glance would miss.
How to build automated, recurring verification rather than relying on manual one-time checks
Scripting the OpenSSL and curl checks covered throughout this guide into a scheduled job that alerts on any unexpected result turns a one-time manual verification into ongoing, automatic assurance that catches a future regression without requiring you to remember to check manually.
Why testing from a genuinely external network perspective catches what local testing misses
Your own local network, office, or home connection may have specific DNS caching, a VPN, or other configuration that doesn't represent what a random visitor elsewhere actually experiences — an independent, externally-hosted testing tool removes this local bias from your verification process.
What a passing SSL scan grade does and doesn't guarantee about real-world security
A high SSL scan grade confirms your TLS configuration meets current best practices for protocol, cipher, and chain configuration — it does not guarantee your application code, server software, or CMS is free of unrelated vulnerabilities, since the scan specifically evaluates TLS configuration rather than your site's broader security posture.
How to interpret conflicting results between two different testing tools
If two SSL testing tools report meaningfully different results, checking each tool's specific criteria and how recently it was updated often explains the discrepancy — testing tools occasionally lag behind the very latest best-practice changes, or weight specific factors differently in their overall scoring methodology.
Why periodic re-verification matters even for a server that hasn't been intentionally changed
A server's TLS configuration can be affected by factors outside your direct control, an OS update changing default cipher support, a certificate renewal picking up different default settings, meaning periodic re-verification catches configuration drift even on infrastructure you haven't deliberately modified recently.
What command-line tools offer beyond what browser-based scan tools can show you
Command-line tools like OpenSSL and curl let you test specific, granular scenarios a browser-based scanner's standardized report doesn't cover, testing a specific cipher suite's availability directly, or checking behavior against a specific TLS version explicitly, giving you more precise diagnostic control when troubleshooting a specific, unusual issue.
How to build verification into your deployment pipeline rather than treating it as a separate step
Adding an automated SSL configuration check as a step in your CI/CD deployment pipeline, failing the deployment if the check doesn't pass, catches a configuration regression automatically before it reaches production, rather than relying on someone remembering to manually re-verify after every deployment.
Why keeping a historical record of past scan results helps spot a gradual configuration decline
Saving scan results over time, rather than only ever looking at the current state, lets you spot a gradual decline, a grade slipping from A+ to A over several months as new best practices emerge and your configuration doesn't keep pace, that a single point-in-time check would never reveal on its own.
What a quick closing checklist for comprehensive SSL verification looks like
A complete verification pass covers: SSL scan tool grade, OpenSSL chain inspection, curl-based redirect status check, DevTools mixed content review, and OCSP stapling confirmation — five independent checks that together catch the categories of failure a single glance at a working page would miss entirely.
Why this guide functions as a capstone for everything else covered in this How-To category
Verification is where every other guide in this category, installation, renewal, format conversion, revocation, ultimately proves out — a correctly completed task in any other guide should pass every check covered here, making this guide a practical way to confirm the rest of your TLS configuration work actually succeeded.
What a complete verification script pulling together every check in this guide looks like
A complete script runs an OpenSSL chain check, a curl-based redirect status check, and an OCSP stapling check in sequence against a given domain, printing a clear pass or fail for each — turning the manual checks covered throughout this guide into a single, repeatable command you can run against any domain on demand.
How to interpret a scan result that changed unexpectedly since your last check
An unexpectedly changed scan result, without any deliberate configuration change on your part, is worth investigating specifically for an OS-level update that altered default cipher support, a certificate renewal that picked up different default settings than the previous issuance, or a scan tool itself updating its own grading criteria — checking the specific grading changelog of your testing tool can rule out the last possibility quickly.