Monitoring production SSL and TLS certificates ensures that public websites maintain valid encryption, avoiding browser security warnings and expired certificate outages. This live lookup tool conducts a remote TLS handshake check against any publicly accessible domain to report certificate parameters and expiration timelines.

### How Remote TLS Handshake Probing Works Because client web browsers operate within a security sandbox that blocks raw TCP socket connections and TLS protocol negotiations to arbitrary remote hosts, this tool utilizes an ephemeral cloud probe: - **SNI Handshake**: Initiates a Server Name Indication (SNI) TLS handshake against the target domain name on port 443. - **Chain Verification**: Inspects the leaf certificate, intermediate certificates, and root Certificate Authority (CA) chain presented during negotiation. - **Cipher Negotiation**: Verifies supported TLS protocol versions (such as TLS 1.2 and TLS 1.3) and active cipher suites. - **Expiration Tracking**: Calculates the exact remaining validity window in days before certificate expiration.

### Worked Inspection Example Enter domain `github.com` and trigger the probe: - **Target Host**: `github.com:443` - **Common Name**: `github.com` - **Issuer**: `DigiCert Global G2 TLS RSA SHA256 2020 CA1` - **Protocol**: `TLS 1.3` - **Certificate Status**: Valid (Expires in 84 days) - **SANs**: `github.com`, `www.github.com`

### Honest Processing Architecture Conducting active network handshakes to remote server ports requires an ephemeral cloud proxy probe. The target domain name is transmitted to this proxy solely to execute the TLS handshake on port 443. The probe does not inspect webpage content, store user identifiers, or persist connection logs.