This is an old revision of the document!
OpenSSL
Useful commands for OpenSSL
CRLs
Parsing a CRL: openssl crl -inform DER -text -noout -in mycrl.crl
PKCS12
Reading a PKCS12 file: openssl pkcs12 -info -in some_file.p12
X.509
Parsing a PEM file: openssl x509 -text -in some_file -inform pem
Connect with TLS
Connect to SMTP: openssl s_client -connect some_domain.tld:587 -starttls smtp
Download certificate (HTTPS w/o SNI): openssl s_client -showcerts -connect some_domain.tld:443 </dev/null
Download certificate (HTTPS w/ SNI): openssl s_client -showcerts -servername some_domain.tld -connect some_domain.tld:443 </dev/null