NetScanTools SSL Certificate Scanner — Quick Guide & Features

NetScanTools SSL Certificate Scanner — Quick Guide & FeaturesNetScanTools SSL Certificate Scanner is a focused utility within the NetScanTools suite that inspects, analyzes, and reports on SSL/TLS certificates used by remote services. This guide explains what the scanner does, how to run scans, important features, practical use cases, interpretation of results, and best practices for certificate management.

What it is and who should use it

NetScanTools SSL Certificate Scanner queries a target host and retrieves the server’s SSL/TLS certificate chain and related connection details. It’s useful for:

• Network administrators verifying certificate deployment across servers.
• Security engineers performing routine or ad-hoc certificate audits.
• IT auditors/compliance teams checking expiration dates and chain validity.
• Help-desk/operations staff troubleshooting client connection problems.

Key features

• Certificate retrieval — pulls the server certificate and the complete chain presented by the server.
• Expiration checks — shows Not Before / Not After dates and highlights certificates near expiration.
• Chain validation — reports whether the presented chain validates to a trusted root (based on local trust store).
• Hostname matching — verifies that the server certificate matches the target hostname (common name and subjectAltName).
• Cipher and protocol info — lists the negotiated TLS version and cipher suite when the scanner performs a live handshake.
• SAN (Subject Alternative Name) listing — enumerates all SAN entries for multi-domain/multi-host certificates.
• Fingerprint and serial — displays SHA-1/SHA-256 fingerprints and certificate serial numbers for inventorying.
• CRL/OCSP status — indicates if certificate revocation checks were performed and their results (when supported).
• Exportable reports — ability to save scan results to text or CSV for auditing and tracking.

How it works (basic flow)

1. The scanner opens a TLS connection to the target host and port (typically port 443).
2. During the TLS handshake, the server sends its certificate chain.
3. The tool extracts certificate fields (subject, issuer, validity, SANs, fingerprints).
4. It may perform additional checks: hostname matching, chain validation against trusted roots, and revocation queries.
5. Results are presented in the UI and can be exported.

Running a scan — step-by-step (typical)

1. Enter target hostname or IP and port.
2. Choose whether to perform a full TLS handshake or a passive retrieval (if available).
3. Enable revocation checks (CRL/OCSP) if you need revocation status — note this depends on network reachability of responders.
4. Start the scan and wait for results.
5. Review certificate chain, expiration dates, SANs, and validation status.
6. Export results if needed for reporting.

Interpreting common results

• Valid chain, hostname matches, not expired — certificate is correctly installed and trusted.
• Hostname mismatch — the certificate does not include the target hostname in CN or SAN; clients will typically warn or block.
• Expired certificate — immediate replacement required to restore trust.
• Untrusted root — the chain does not validate to a root in the scanner’s trust store; may indicate a missing intermediate or use of a private CA.
• Revoked — certificate has been revoked via CRL/OCSP; stop using it and investigate.
• Weak cipher/protocol — shows if the server negotiates deprecated protocols (e.g., SSLv3, TLS 1.0) or weak ciphers — consider upgrading server configuration.

Practical use cases

• Scheduled certificate inventory scans to catch near-expiry certificates.
• Verifying new deployments before moving services to production.
• Troubleshooting user connection issues reporting certificate name mismatches or trust errors.
• Compliance checks for minimum TLS versions and cipher strength.
• Spotting servers that present incorrect or incomplete chains (missing intermediates).

Best practices when using the scanner

• Run periodic automated scans (weekly/monthly) to detect upcoming expirations.
• Combine scanner output with monitoring alerts tied to expiration thresholds (e.g., 30/14/7 days).
• Verify revocation checks from the same network location clients use (CRL/OCSP responders may be blocked by firewalls).
• Keep the scanner’s trust store updated to reflect current CA changes.
• When fixing issues, always re-scan after changes to confirm proper installation.

Limitations and caveats

• Chain validation depends on the scanner’s trust store and may differ from client devices’ trust stores.
• OCSP/CRL checks rely on network access to responders; lack of reachability can make revocation status unknown.
• Some servers use SNI to present different certificates; you must specify the correct hostname to get the intended certificate.
• The scanner reports what the server presents — it cannot detect client-side misconfigurations or intercepted TLS if a man-in-the-middle is in place unless the presented certificate indicates it.

Example output fields (what to expect)

• Target host and port
• TLS protocol and cipher negotiated (if handshake performed)
• Certificate subject and issuer
• Not Before / Not After dates
• SAN entries
• Fingerprints (SHA-1, SHA-256)
• Serial number
• Chain validation result
• Revocation (CRL/OCSP) status
• Hostname match result

Quick troubleshooting checklist

• If hostname mismatch: check server virtual host/SNI configuration and certificate SANs.
• If chain untrusted: ensure intermediate certificates are installed on the server in the correct order.
• If expired: renew via your CA and install new cert and chain.
• If revocation unknown: confirm outbound access to CRL/OCSP responders.
• If weak ciphers: update server TLS configuration to prioritize modern cipher suites and TLS 1.⁄₁.3.

Summary

NetScanTools SSL Certificate Scanner is a practical tool for inspecting certificates, validating chains, checking expirations, and uncovering common TLS configuration problems. Use it regularly as part of certificate lifecycle management and combine results with automated alerts and re-checks after remediation to maintain secure, trusted services.