Conclusion
In this article, I showed you how to provision and configure a cloud-based server running the CentOS 7 linux distribution. I showed how to add multiple domains, configure mail and web services and install and configure both a WordPress site as well as a Roundcube installation. I also showed how to best secure the system using a combination of non-root users, alternate service ports, and the implementation of fail2ban. At this point you should have a working web- and mail-enabled multi-domain server.
I use Exim as mail server and I installed opendkim using the instructions at
https://www.rosehosting.com/blog/how-to-install-and-configure-dkim-with-opendkim-and-exim-on-a-centos-7-vps/
Awesome! To be perfectly honest, i went with postfix because it’s been the default I’ve seen installed with Virtualmin. Why did you choose to go with exim?