I've used ISPConfig now for about a year. I recently reinstalled onto a Debian 12 server and went deeper into setting it up. I've now seen that the proper way to access webmail is on port 8081 like this... https://FQDN:8081/webmail/ I don't use webmail too often, but occasionally, I've needed to use it. I didn't even know about port 8081 last year, and just went to webmail like this...https://domain.com/webmail/ and it works perfectly and is indeed using a secure SSL connection to the mail server. So my observation was that a customer could just use his/her own domain name with /webmail/ and access webmail and feel like they are branded to their own domain name. My intention was to instruct my customers to use the FQDN as the hostname for their mail client, and to access their webmail with their own domain name like this... https://example.com/webmail/ I have also figured out that you really DO need to use the FQDN for the mail server in the mail client in order to access the email server via SSL with your mail client. Accessing the mail server with client's own domain will "work" but you will have to see the message about the SSL registered to the FQDN and of course not to the client's domain name. The reason I am asking is every mention for accessing webmail is to use https://FQDN:8081/webmail/ and I've not seen mention to ever use https://example.com/webmail/ Will I be introducing an unforeseen problem if I tell customers to access webmail like that? Am I wrong? So ultimately, my question it can I tell my customers to access webmail with their own domain name like this? https://example.com/webmail/ It's how I access my webmail, when I need it.
As long as you do not use Nginx as a web server and as long as you do not turn on Chrooting for PHP to secure the website, then this will likely work in most cases. But you must be aware that your customers can potentially have rewrite rules in place that might cause webmail to fail as well. So if you want to run a hosting business, then I would not tell customers to use /webmail in their domain as this will not always work and you might get a lot of support requests to explain users why they can not reach webmail under certain circumstances. If you don't like port 8081 in the URL, then create a website webmail.yourcompanydomain.tld and install a webmail client of your choice in it. Using a subdomain of your company domain for webmail, as larger ISP's do, will also strengthen your brand.
