Openssl

How to test SSL connectivity

---

openssl s_client -showcerts -connect <ip>:<port>

# force tls1.2:
openssl s_client -tls1_2 -showcerts -connect <ip>:<port>

How to check if SSL certificate on an instance has expired

---

openssl s_client -connect ec2-x-x-x-x.eu-west-2.compute.amazonaws.com:443 -servername dikapedia.com 2>/dev/null | openssl x509 -noout -dates -issuer -subject
       notBefore=Oct  1 11:59:06 2021 GMT
       notAfter=Dec 30 11:59:05 2021 GMT
       issuer= /C=US/O=Let's Encrypt/CN=R3
       subject= /CN=dikapedia.com