Thank you all for these first answers. I also had checked out about radicale and baikal, while completely forgotten about sogo.
Concerning this latter one I downloaded the .ova of ZEG just to give it a try and I found its management through webmin cumbersome (e.g. the interface for users' management of LDAP database didn't connect with it, etc.). As people honestly wrote in forums, to have zeg adapted takes the guys of inverse who produce it to tie it to another domain and customize it for you. But I don't really wanna run on Ubuntu. Plus I don't need either mail management or any domain thereof. Here I come to the real need: giving a small group of volunteers (no more than 20) who mostly operate with iCal but also outlook (it's a scattered group) the ability to coordinate their social activity together by: 1. creating events with attendees on 2/3 calendars over which some users are rw and others ro 2. send invitations to the outside world (could be 50-100 people) when they want to make a public event all together and get answers also from from invitees who are not davical/baikal/radicale users (although this should be managed by the client and not by the server, true?) I thought that a lightweight product like davical, radicale or baikal would be better fit to manage, but it's the first time I try this thing. Honestly I don't know which one of them better fills the bill. *** especially on openbsd *** At the moment I was trying both davical and baikal, configuring them with nginx, considering that openbsd has quit apache and that nginx is the web server I have had most experiences with (and that the new httpd is so new that it is a completely unsupported config). In the first case I arrived where the setup.php complains it cannot attach to the database, in the second one, using the same nginx.conf provided with the package files, the webpage is fixed on error 502. My sensation is that these products are extremely messy to configure as their laconic install documents leave most of the details uncovered. I am following the few hints found in /usr/local/share/doc/pkg-readmes/ as the rest of the docs (e.g. INSTALL from package dir, webpages) are mostly linux-centric, so they are useful more for inspiration rather than step-by-step procedure. One of the details I find nowhere, for instance, is about the permissions that the files should be given: installed from packages most files are either root:bin or root:daemon while tutorials often say they should be www:www (exactly www-data:www-data as they're linux-centric). Another doubt that I have is about backups and troubleshooting. I have no idea which product would be easier/more consistent to manage, especially in a disaster recovery scenery and in a half yearly upgrade one. Surely, the idea that under davical runs pg looks like more thorough than some sqlite or different, but things at least things have to work. To which point I am not yet. Looking forward for your further inspiration. Thanks
