Certificate

Install certbot

apt-get install certbot

Request a wildcard certificat

certbot certonly --manual --preferred-challenges=dns --email webmaster@objclt.ca --server https://acme-v02.api.letsencrypt.org/directory --agree-tos -d *.objclt.ca

Update your DNS

Please deploy a DNS TXT record under the name _acme-challenge.objclt.ca with the following value:

d2MbmqrvfiohoavRiquicUZZXCfKda5ApasdaafI (DO NOT USE THAT VALUE !!!)

Before continuing, verify the record is deployed.

_acme-challenge.objclt.ca.	IN	TXT	"d2MbmqrvfiohoavRiquicUZZXCfKda5ApasdaafI"

certificate generated

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/objclt.ca-0001/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/objclt.ca-0001/privkey.pem
   Your cert will expire on 2020-01-10. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot
   again. To non-interactively renew *all* of your certificates, run
   "certbot renew"
 - If you like Certbot, please consider supporting our work by:

   Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate
   Donating to EFF:                    https://eff.org/donate-le

Validate the certificate

openssl s_client -crlf -connect mail.objclt.ca:993
openssl s_client -connect mail.objclt.ca:[port] -servername mail.objclt.ca

• Tools to validate configuration
  • ssl-tools
  • CheckTls
  • MxToobox
  • ImmuniWeb