Stefan Hornburg (Racke)
OpenSSL Usage
Useful site with SSL commands, CSR and certificate decoder:
https://redkestrel.co.uk/articles/openssl-commands/
Display certificate request:
openssl req -noout -text -in /etc/apache2/ssl/server2016.csr
Display to whom it was issued from PEM file:
openssl x509 -noout -in imapd.pem -subject
Display certificate:
openssl x509 -noout -text -in /etc/apache2/ssl/server2016.crt
Create key:
openssl genrsa 2048 > www.linuxia.de.key
Create certificate request from existing key (SHA2):
openssl req -new -key www.linuxia.de.key -sha256 -out server2016.csr
Create certificate request from existing certificate and key:
openssl x509 -x509toreq -in www.linuxia.de.crt -out www.linuxia.de.csr -signkey www.linuxia.de.key
Show public key information:
openssl rsa -in www.linuxia.de.key -pubout
Test SSL connection and print out SSL certificate:
openssl s_client -connect 192.168.26.241:443
Connect to SMTP server with STARTTLS:
openssl s_client -connect 192.168.26.241:25 --starttls smtp
For more information, check the OpenSSL Command-Line HOWTO.