10 TLS Security Checks for Linux and Windows
TLS checks are easy on one endpoint and awkward across a mixed estate. Linux and Windows services expose different failure modes, especially when HAProxy, Nginx, IIS, and private services all sit in the same environment.
These checks are intentionally practical. They are the things that stop 3am certificate incidents and embarrassing audit gaps.
TLS check sequence
TLS issues these checks catch
The common failure.
Leaf is valid but clients still fail.
Service did not reload new material.
Nobody receives the alert.
The ten checks
Check hostname/SNI, SANs, issuer, full chain, expiry, private key match, protocol versions, cipher policy, service reload, live endpoint result, and ownership. If that sounds like eleven, good: TLS work always hides one more detail.
CertLocker helps by keeping inventory, delivery, endpoint probes, and audit records tied together.
Linux and Windows fail differently
On Linux, the problem often lives in file paths, PEM bundles, reload commands, and multiple reverse proxies. On Windows, IIS bindings, certificate stores, and win-acme tasks matter.
A useful TLS process handles both without forcing one operating model onto the other.
Make the probe part of the workflow
Do not treat endpoint checks as a manual debugging step. Run them after renewal and delivery so the team knows what clients actually see.
That proof is useful for incident response and for ISO 27001-style evidence around operational controls.
The 10 TLS checks
- ✓ Hostname and SNI route are correct.
- ✓ SANs cover the real service names.
- ✓ Issuer and chain are expected.
- ✓ Certificate is not near expiry.
- ✓ Private key matches the certificate.
- ✓ Protocol and cipher policy are acceptable.
- ✓ HAProxy, Nginx, IIS, or app service reloaded.
- ✓ Endpoint probe matches inventory.
- ✓ Owner and alert route are set.
- ✓ Audit trail records the change.
Related reading and workflows
Certificate lifecycle management
Inventory, renewal, delivery, ownership, and audit for TLS certificates.
Certificate delivery tokens
Scoped certificate access for HAProxy, IIS, Nginx, scripts, and automation.
Endpoint probes
Check what production endpoints actually serve after renewal.
Help with onboarding
Bring your existing inventory to a hosted walkthrough with the CertLocker engineers.
CertLocker for DevOps teams
The broader trust-control workflow for platform and infrastructure teams.
Compare CertLocker with scripts
Where spreadsheets, cron jobs, and shared files stop being enough.
Try the workflow against real infrastructure
Use the hosted evaluation at trust.certlocker.io for a walkthrough, or run a one-month onsite evaluation against your own certificates, hosts, secrets, and access paths.