Verifying OpenSSL certificates

Verifying that a certificate is issued by a CA

How to use OpenSSL on the command line to verify that a certificate was issued by a specific CA, given that CA's certificate:

$ openssl verify -verbose -CAfile cacert.pem  server.crt
server.crt: OK

Verify that a private key matches a certificate

$ openssl x509 -noout -modulus -in server.crt | openssl md5
$ openssl rsa -noout -modulus -in server.key | openssl md5

The resultant hashes should match.