Openssl

https://www.redhat.com/sysadmin/6-openssl-commands

Extract cert and key

openssl pkcs12 -in domain.pfx -clcerts -nokeys -out domain.crt
openssl pkcs12 -in domain.pfx -nocerts -nodes  -out domain.key   

Update your Apache configuration file with:

<VirtualHost 192.168.0.1:443>
 ...
 SSLEngine on
 SSLCertificateFile /path/to/domain.crt
 SSLCertificateKeyFile /path/to/domain.key
 ...
</VirtualHost>

echo quit | openssl s_client -connect log.example.com:6514
echo "Q" | openssl s_client -servername google.com -connect google.com:443 | openssl x509 -noout -dates

echo quit | openssl s_client -showcerts -servername server -connect google.com:443 > cacert.pem
true | openssl s_client -connect google.com:443 2>/dev/null | openssl x509
rm -f cert.pem && echo -n | openssl s_client -connect google.com:443 | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > ./cert.pem

curl --cacert google.pem https://google.com

openssl s_client -connect 10.x.x.x:6514

PKI

#!/usr/bin/env bash
set -eu
# ref: https://datacenteroverlords.com/2012/03/01/creating-your-own-ssl-certificate-authority/

bits=4096
# cert_cn=insights.mktp.io
rootCA_dir=rootCA
keys_dir=rootCA/keys
mkdir -p $rootCA_dir
mkdir -p $keys_dir
# cd $rootCA_dir
ca_subject="-subj \"/C=US/ST=Utah/L=SLC/O=UVOO/OU=IT/CN=ca.example.com\""


create_CA(){
  echo "Configuring rootca certs for issueing certs to nodes via CN/fqdn."
  openssl genrsa -out $rootCA_dir/rootCA.key $bits
  openssl genrsa -des3 -out $rootCA_dir/rootCA.key $bits
  # openssl genrsa -nodes -out $rootCA_dir/rootCA.key $bits
  # openssl req -x509 -new -nodes -key $rootCA_dir/rootCA.key -sha256 -days 10240 -out $rootCA_dir/rootCA.pem $ca_subject
  openssl req -x509 -new -nodes -key $rootCA_dir/rootCA.key -sha256 -days 10240 -out $rootCA_dir/rootCA.pem -subj "/C=US/ST=Utah/L=SLC/O=example/OU=IT/CN=ca.example.com"
}


create_client(){
  cert_cn=$1
  echo "Configuring certs for nodes with CN/fqdn."
  openssl genrsa -out $keys_dir/${cert_cn}.key $bits
  openssl req -new -key $keys_dir/${cert_cn}.key -out $keys_dir/${cert_cn}.csr -subj "/C=US/ST=Utah/L=SLC/O=EH/OU=IT/CN=$cert_cn"
  openssl x509 -req -in $keys_dir/${cert_cn}.csr -CA $rootCA_dir/rootCA.pem -CAkey $rootCA_dir/rootCA.key -CAcreateserial -out $keys_dir/${cert_cn}.crt -days 730 -sha256
}

copy_keys_to_rsyslog(){
  cp $keys_dir/${cert_cn}.key ../files/etc/rsyslog.d/keys/
  cp $keys_dir/${cert_cn}.crt ../files/etc/rsyslog.d/keys/
  cp $rootCA_dir/rootCA.pem ../files/etc/rsyslog.d/keys/
}

create_CA
create_client insights.example.com
copy_keys_to_rsyslog

# sudo openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /etc/ssl/private/nginx-selfsigned.key -out /etc/ssl/certs/nginx-selfsigned.crt