
http://www.yourserver.com/.well-known/acme-challenge/FgedPYS65N3HfwmM7IWY2...
- You can use your domain hosting service (GoDaddy, Whois, etc.) to create a new TXT record.
- The "certbot" command line client does all the rest in just one call.
- Under Debian 9 and 10, "certbot" is part of the official package repository.
- You can run certbot on any Linux client. You don't have to run it on the email server.
Example
# certbot certonly --manual --preferred-challenges dns -d mx.yourserver.com Saving debug log to /var/log/letsencrypt/letsencrypt.log Plugins selected: Authenticator manual, Installer None Obtaining a new certificate Performing the following challenges: dns-01 challenge for mx.yourserver.com - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - NOTE: The IP of this machine will be publicly logged as having requested this certificate. If you're running certbot in manual mode on a machine that is not your server, please ensure you're okay with that. Are you OK with your IP being logged? - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - (Y)es/(N)o: Y - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Please deploy a DNS TXT record under the name _acme-challenge.mx.yourserver.com with the following value: 1A4RACHEISTBLUTWURST_egTVadkeiieikeieisfkfk Before continuing, verify the record is deployed. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Press Enter to Continue Waiting for verification... Cleaning up challenges IMPORTANT NOTES: - Congratulations! Your certificate and chain have been saved at: /etc/letsencrypt/live/mx.yourdomain.com/fullchain.pem Your key file has been saved at: /etc/letsencrypt/live/mx.yourdomain.com/privkey.pem Your cert will expire on 2020-02-15. 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