Hi. If you're talking about having dedicated subdomains, ie webmail.domain.tld, you'll have to set it up manually. First, you'll have to create a vhost for apache, ususally in /etc/apache2/sites-availlable/ you could name it roundcube.vhost Code: <VirtualHost *:80> ServerName webmail.domain.tld ServerAlias webmail.domain2.tld ServerAlias webmail.domain3.tld etc... DocumentRoot /var/lib/roundcube <Directory /var/lib/roundcube> Options FollowSymLinks AllowOverride All Order allow,deny Allow from all </Directory> </VirtualHost> then you restart Apache (on Ubuntu with "systemctl restart apache2") Then, you can use Certbot to generate the certificate : Code: certbot certonly --cert-name roundcube --webroot -w /usr/local/ispconfig/interface/acme/ -d webmail.domain.tld -d webmail.domain2.tld -d webmail.domain3.tld The path after -w is important because it is fixed by ispconfig configuration. Once the certificate is generated, you can modify your apache vhost, keeping an http section on port 80 to redirect to https : Code: <VirtualHost *:80> ServerName webmail.domain.tld ServerAlias webmail.domain2.tld ServerAlias webmail.domain3.tld RewriteEngine on RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [L,QSA,R=permanent] </VirtualHost> <VirtualHost *:443> ServerName webmail.domain.tld ServerAlias webmail.domain2.tld ServerAlias webmail.domain3.tld Protocols h2 http/1.1 DocumentRoot /var/lib/roundcube <Directory /var/lib/roundcube> Options FollowSymLinks AllowOverride All Order allow,deny Allow from all </Directory> SSLEngine On SSLCertificateFile /etc/letsencrypt/live/roundcube/fullchain.pem SSLCertificateKeyFile /etc/letsencrypt/live/roundcube/privkey.pem </VirtualHost> This is the lazy single certificate solution. If you care about not sharing a certificate for all your clients, you can generate individual <virtualhost> sections for each subdomain, and individual certificates instead of using a global "roundcube" one. (This would be worth a plugin)
You can do this through the UI, there are several ways to do that. So I would strongly advice you to do it through the UI.
Some ideas: - Add a website "webmail.example.com", enable LE, and add your clients domains as alias - (wildcard SSL cert required) enable the wildcard as subdomain for all sites and add a redirect for webmail. to the vhost through a custom vhost.conf.master - Redirect /webmail for all clients to webmail.example.com (recommended way). You can follow this guide: https://www.howtoforge.com/community/threads/redirect-webmail-to-webmail-example-com.86368/
