Hello I have to migrate multiple domain on ispconfig. All my customer got a separate domain Example: firstdomain.com seconddomain.com thirddomain.com etc... It works perfectly for the web. Each website got the right certificat (LetsEncrypt) for the domain. ************************************ Now for email server, following your manual, we have to use only the certificate of isp-config. The problem is that all of my customer are using the server name corresponding to the domain (mail.firstdomain.com , mail.seconddomain.com, etc) in their mail settings (Thunderbird, Outlook, etc) When i will migrate all this customer, i will have to change all settings of my customers. It will be very hard, to do it (i got many customer). Is it not possible to use the same certificat, create for the website? Like this all my customer will not have to change all settings of their mail account. Or there is an other solution? I hope you understand my bad english (sorry) Best regards and thanks for your help.
Hello If i understand correctly this configuration, i have to use one domain for all of my customer, even if they have a domain? I create a server like serverforall.com, put the certificate for serverforall.com, and then all my customer have to use this server, with the right certificat, to configure their email client? Best regards and thanks for your help.
Yes and that basically is the ISPConfig default setup, except it uses subdomain and not main domain, which is the best approach. Multiple domains, if you wish to use, though highly not advisable, is in the link suggested above by @till.
You don't have to, but its easier and better for you and your customers if you do this. You can use customer domains, see link I posted above. But the mail system has just a single SSL cert, so all customer domains must be added by you to this single SSL cert and also be removed if a customer leaves you and if a customer would change DNS for one of his domains, the SSL cert renewal will fail for all customers and your mail system will be unreachable. A single cert also imposes limits on how many email domains you can have. Therefore, this solution is not recommended and usually not used. You never use a domain directly for this, the server hostname is always a subdomain. So you would not use serverforall.com but something like mail.serverforall.com for your email system and all your customers use mail.serverforall.com in their mail clients.
The problem, is that i have to migrate hundred domains (is not new customers), and all, have already, in their settings, mail.firstdomain.com , mail.seconddomain.com, etc If i can use the same server name with the right certificat, the job will be easiest. If i use one certiifcat, for all server, i have to change the email settings for all of my clients. But i understand your approach Thanks a lot
A Let's encrypt SSL cert can contain max. 100 domains (or subdomains), so you would reach that limit already. If you can not use a single domain name, then your only chance is to configure SSL certs manually in postfix and dovecot. Most recent postfix versions have multi SSL cert support now, older versions do not have this option. You would then use a setup like this: https://serverfault.com/questions/920436/set-up-certs-for-multiple-domains-in-postfix-and-dovecot https://medium.com/better-coder/postfix-multiple-domain-ssl-certificates-89c9f186ed73
