Read the SSL Certificate information from a remote server
You may want to monitor the validity of an SSL certificate from a remote server, without having the certificate.crt text file locally on your server? You can use the same openssl for that.
To connect to a remote host and retrieve the public key of the SSL certificate, use the following command.
$ openssl s_client -showcerts -connect ma.ttias.be:443
This will connect to the host ma.ttias.be on port 443 and show the certificate. It’s output looks like this.
$ openssl s_client -showcerts -connect ma.ttias.be:443 -----BEGIN CERTIFICATE----- MIIEzTCCA7WgAwIBAgISESHAjlbjcoBHxBYXS12oY6VjMA0GCSqGSIb3DQEBCwUA ... CzgXBhDR3themzPx4jwx2ckNFpNDK/6yQgrKaHTewAAj -----END CERTIFICATE----- --- Server certificate subject=/C=BE/OU=Domain Control Validated/CN=ma.ttias.be issuer=/C=BE/O=GlobalSign nv-sa/CN=AlphaSSL CA - SHA256 - G2 ---