TLS certificate check

Chain, names, expiry and protocol support.

What this check does

Completes a TLS handshake with server name indication and inspects the certificate the way a browser would, then tests which protocol versions the server accepts.

Certificate subject, issuer, validity and days left
Subject alternative names and hostname match
Chain verification against public roots
Key type and size, signature algorithm
TLS 1.0 to 1.3 support