tlsinfo: show TLS version, cipher, and peer certificates
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Description
tlsinfo connects to a TLS server and prints the negotiated TLS version and
cipher suite, followed by details for each certificate in the server’s
presented chain (as provided by the server).
Usage
tlsinfo <hostname:port>
Output
The program prints the negotiated protocol and cipher, then one section per
certificate in the order received from the server. Example fields:
TLS Version: TLS 1.3
Cipher Suite: TLS_AES_128_GCM_SHA256
Certificate 1
Subject: CN=example.com, O=Example Corp, C=US
Issuer: CN=Example Root CA, O=Example Corp, C=US
DNS Names: [example.com www.example.com]
Not Before: 2025-01-01 00:00:00 +0000 UTC
Not After: 2026-01-01 23:59:59 +0000 UTC
Examples
# Inspect a public HTTPS endpoint
tlsinfo example.com:443
Notes
- Verification is intentionally disabled (InsecureSkipVerify=true). The tool
does not validate the server certificate or hostname; it is for inspection
only.
- The SNI/ServerName is inferred from <hostname> when applicable.
- You must specify a port (e.g., 443 for HTTPS).
- The entire certificate chain is printed exactly as presented by the server.
