CIRCUITO
CARIOCA TI · DOCUMENTATION
♙
Web security

SSL/TLS Certificate Checker

Validate a TLS connection and inspect certificate identity, issuer, validity, SANs, negotiated protocol and cipher.

TLSSSLCertificateSANX.509

TLS certificate inspection

Connects to port 443 with certificate-chain and hostname verification enabled.

Enter only a hostname. Port 443 is used and private/reserved destinations are blocked.
TLS

The connection validates both the trust chain and hostname

The PHP TLS context keeps peer verification and peer-name verification enabled. A certificate signed by a trusted CA is therefore not enough: its identity must also match the hostname requested by the user.

SAN

Subject Alternative Names are the primary identities to inspect

Modern certificates normally carry DNS identities in the Subject Alternative Name extension. A certificate can cover several names and wildcards, so the Common Name alone is not a complete representation of its hostname coverage.

DNS SAFETY

The destination is pinned to a validated public IP

Before TLS starts, the page resolves every A and AAAA record and rejects the hostname if any address is private or reserved. The socket is then opened directly to one validated literal IP, while SNI and hostname validation keep using the original hostname.

NEGOTIATION

Protocol and cipher describe this specific handshake

The protocol and cipher displayed are those negotiated between this portal server and the destination during this connection. They do not enumerate every TLS version or cipher suite supported by the remote service.

SECURITY POSTURE

A valid certificate is only one layer of web security

A valid TLS certificate does not prove that an application is secure. Protocol policy, cipher configuration, HSTS, certificate lifecycle, HTTP security headers and application vulnerabilities remain separate concerns.

FAQ

Frequently asked questions

Does the tool verify the certificate hostname?+

Yes. PHP peer-name verification stays enabled and the requested hostname is explicitly used as peer_name and SNI.

Why connect to an IP if the certificate belongs to a domain?+

The page resolves and validates DNS first, then connects to the validated literal IP to avoid a second destination-changing DNS lookup. Hostname verification and SNI still use the original domain.

What is SAN?+

Subject Alternative Name is the certificate extension that normally lists the DNS names and sometimes IP identities covered by the certificate.

Does the displayed cipher show every cipher supported by the server?+

No. It is only the cipher negotiated for this specific handshake between the portal server and the destination.

Why can a valid website fail here?+

The portal server may have a different CA store, DNS view, IPv4/IPv6 path or network policy. A temporary remote or local connectivity problem can also cause failure.

Does the tool test certificate revocation?+

No explicit OCSP or CRL status is reported by this page. The result should not be interpreted as a complete revocation audit.

Does a valid TLS certificate mean the website is secure?+

No. It validates an important transport-security property, but application vulnerabilities, headers, HSTS, protocol policy and many other controls are separate.