LetsEncrypt now supports / issues wildcard SSL certificates. If you have been a letsencrypt user then you will very much welcome this feature. So lets start with how to do this.
It is assumed that the naked domain (non-www domain for example, btrnaidu.com) is been forwarded to valid subdomain (www for example, www.btrnaidu.com)
Wildcard SSL Cert for btrnaidu.com domain:
# ./certbot-auto –server https://acme-v02.api.letsencrypt.org/directory -d *.btrnaidu.com –manual –preferred-challenges dns-01 certonly
Wildcard SSL Cert for btrnaidu.com and amstar.in domain:
# ./certbot-auto –server https://acme-v02.api.letsencrypt.org/directory -d *.btrnaidu.com -d *.amstar.in –manual –preferred-challenges dns-01 certonly
Follow the output by command and verify the domain ownership by adding TXT records. Once done, the certs will be produced.
Copy the certs to your web-server and viola.. You have a wild card cert for your domain now.