OpenSSL
From Lolly's Wiki
Verify
# openssl verify -CAfile /srv/www/htdocs/pub/RHN-ORG-TRUSTED-SSL-CERT /etc/pki/spacewalk/jabberd/server.pem
# openssl crl2pkcs7 -nocrl -certfile /srv/www/htdocs/pub/RHN-ORG-TRUSTED-SSL-CERT | openssl pkcs7 -print_certs -noout -print_certs
CSR
Create key and CSR
$ subject_without_cn='/C=DE/ST=Hamburg/L=Hamburg/O=Organisation/OU=Team'
$ declare -a hosts=( "name1.server.de" "name2.server.de" )
$ openssl req -newkey rsa:4096 -sha256 -keyout ${hosts[0]}-key.pem -out ${hosts[0]}-csr.pem -batch -subj "${subject_without_cn}/CN=${hosts[0]}" -reqexts SAN -config <(cat /etc/ssl/openssl.cnf <(printf "[SAN]\nsubjectAltName=DNS:${hosts[0]}${hosts[1]:+,DNS:${hosts[1]}}${hosts[2]:+,DNS:${hosts[2]}}${hosts[3]:+,DNS:${hosts[3]}}${hosts[4]:+,DNS:${hosts[4]}}"))
Verify your CSR
$ openssl req -text -noout -verify -in ${hosts[0]}-csr.pem
