I believe this could be done, but not sure how. I want a mail server node on one Virtualmin location, the dns server node on a different Virtualmin location, and everything else on a different Virtualmin location. Is this possible, and if so please show me.
DNS is easy. Trivially so.
Mail is…difficult and has trade-offs. You’d need a central user store, like LDAP. I don’t recommend it, if you don’t really need it, as it adds a lot of complexity.
Databases are almost as easy as DNS, though.
Cloudmin Pro has Connect, which manages DNS and databases (and mail scanning, but not mail hosting) for many Virtualmin hosts, but you can do DNS and databases with just Webmin on the DNS and database servers, as well…just takes a couple minutes to see it up on each new Virtualmin host.
My isp on doesn’t allow mail server to be hosted with business accounts.
As @calport correctly notes, that’s a different problem/question, and the answer is relaying, which can go both directions.
But, I would also recommend you consider putting your server somewhere with a fully functional network. Technology is hard enough without your tools actively fighting you.