TLS 클라이언트 연결을 생성하는 OpenSSL 명령어. 더 많은 정보: https://www.openssl.org/docs/manmaster/man1/openssl-s_client.html.
openssl s_client -connect {{호스트}}:{{포트}} 2>/dev/null | openssl x509 -noout -dates
openssl s_client -connect {{호스트}}:{{포트}} </dev/null
openssl s_client -connect {{호스트}}:{{포트}} -servername {{호스트명}}
openssl s_client -connect {{호스트}}:443 -showcerts </dev/null