Certificate

Security Certificate

To configure a SSL certificate for TLS and/or SSL over SMTP:

1. Abstract: Create Certificate

   Generate key

   Generate signing request

   Sign the key

   Create server certificate

   Set permission

   Set owner

   Copy into place

   Restart services

   1. Self-Signed Certificate

      # openssl genrsa -out x.key 2048

      # openssl req -new -key x.key -out x.csr

      # openssl x509 -req -days 3650 -in x.csr -signkey x.key -out x.crt

      # cat x.crt x.key > servercert.pem

      # chmod 644 servercert.pem

      # chown root:qmail servercert.pem

      # cp -p servercert.pem /var/qmail/control

   2. Let's Encrypt CentOS 7/8 (Automatic, assumes working web server)

      # yum install python-certbot-apache

      # certbot -apache -d mydomain.com -d mail.mydomain.com

      Add to Apache Virtual

      SSLCertificateFile /etc/letsencrypt/live/mydomain.com/cert.pem

      SSLCertificateKeyFile /etc/letsencrypt/live/mydomain.com/privkey.pem

      SSLCertificateChainFile /etc/letsencrypt/live/mydomain.com/fullchain.pem

      Add to Dovecot

      ssl_cert = </etc/letsencrypt/live/mydomain.com/fullchain.pem

      ssl_key = </etc/letsencrypt/live/mydomain.com/privkey.pem

      Add to Qmail

      # cp -p /var/qmail/control/servercert.pem /var/qmail/control/servercert.pem.bak

      # cat /etc/letsencrypt/live/mydomain.com/privkey.pem /etc/letsencrypt/live/mydomain.com/fullchain.pem > /var/qmail/control/servercert.pem

      Springdale, Rocky, Alma Linux 9 may need the private key last

      # cat /etc/letsencrypt/live/mydomain.com/fullchain.pem /etc/letsencrypt/live/mydomain.com/privkey.pem > /var/qmail/control/servercert.pem

      Let's Encrypt auto renewal

      Add to cron nightly renew of certs (These certificates expire every 3 months)

      0 0 * * * /opt/certbot/certbot renew

   3. Application: Godaddy Signed Certificate

      # openssl genrsa -out x.key 2048

      # openssl req -new -key x.key -out x.csr

      Submit signing request (x.csr) to Godaddy; Later download signed key (crt and crt bundle)

      # cat x.key 7531fdb8504afe19.crt gd_bundle-g2-g1.crt > servercert.pem

      # chmod 644 servercert.pem

      # chown root:qmail servercert.pem

      # cp -p servercert.pem /var/qmail/control

2. Restart Qmail and Dovecot

   # qmailctl stop && sleep 2 && qmailctl start

   # systemctl restart dovecot

   # systemctl restart httpd