Check live TLS cert

Show expiry and issuer of a live TLS certificate

echo | openssl s_client -connect example.com:443 -servername example.com 2>/dev/null | openssl x509 -noout -dates -subject -issuer
tool
openssl27 commands
tags
opensslsecuritynetwork

More openssl commands

  • Check full cert chain
    openssl s_client -connect example.com:443 -showcerts 2>/dev/null | openssl crl2pkcs7 -nocrl | openssl pkcs7 -print_certs -noout -text | grep -E 'Subject:|Issuer:'

    Display full chain: leaf → intermediate → root

  • Encrypt file with AES-256
    openssl enc -aes-256-cbc -pbkdf2 -in secret.txt -out secret.enc

    Password-encrypt a file with AES-256-CBC + PBKDF2

  • Decrypt AES-256 file
    openssl enc -d -aes-256-cbc -pbkdf2 -in secret.enc -out secret.txt

    Decrypt a file encrypted with the enc command above

  • Generate random hex token
    openssl rand -hex 32

    Generate a 64-char hex random string (e.g. for API keys)

  • Full certificate inspect
    openssl x509 -in cert.pem -noout -text

    Dump all cert fields: subject, issuer, validity, extensions, SANs, key usage

all 27 openssl commands