FreeBSD: Using Open-Xchange on FreeBSD
If you go looking for a usable webmail application, then you might end up with Open-Xchange (OX for short). Some larger ISP’s are using OX as their webmail application for customers. It has a multitude of options available, using multiple email accounts, caldav/carddav included (not externally (yet?)) etc. There are commercial options available for these ISP’s, but also for smaller resellers etc. But, there is also the community edition available. Which is the installation you can run for free on your machine(s). It does not have some of the fancy modules that large setups need and require, and some updates might follow a bit later which are more directly delivered to paying customers, but it is very complete and usable. ...