I have been searching far and wide for a decent cross-platform calendar server that’s CalDAV compatible. We use Groupwise at work, which is great for Windows clients. Anyone who’s used the Mac and Linux client knows that it’s just not a good experience. There are several features offered in the Windows client that are lacking in OS X and Linux. Does anyone else find that odd considering Groupwise is a Novell product? There IS the SOAP port possibility, but the Groupwise admins refuse to open it for reasons I’m not aware of.
- Darwin Calendar Server – this is the same exact (actually newer) server as what Apple offers on OS X Leopard Server, sans the GUI. It’s python based, and the Wiki contains the basic stuff you need to know to get it up and running.
- Cosmo Calendar Server – part of the Chandler project. It’s java based, and looks promising. Last I looked into it, it was very early alpha. It seems to have made a bit of progress since then. Now it seems to offer an all around solution: a client and server, as well as a free (for now) hosted server called Chandler Hub.
- Bedework - a calendar server also built on java with CalDAV support. We tried setting this up in our offices once, but Tomcat kept crashing. I might try again from source.
- DAViCal – another CalDAV server. I haven’t tried it out because I’m not very proficient with PostgreSQL.
- Zimbra – A bit overkill for someone looking for just a calendar server, but it’ll get the job done with a web interface and CalDAV support.
- OS X 10.5 Server – Much more than a calendar server, but it’ll get the job done. Basically gives you a GUI to Darwin Calendar Server, I think.
- Nighthawk – One of my top choices for a commercial calendar server and client. It’s not available yet, but from what I’ve seen it will be fantastic.