Application of choice is radicale. Lightweight, filesystembased storage and localusers. Well suited for large but also for small environments. Implements only the serverside part of the functionality.

Use a minimal debian-8 (jessie). This version has the latest version 0.8 of radicale in the repository.

Install the software with:

apt-get install  radicale python-radicale

This creates also an operatingsystem user and group radicale, a convenient start-script, and a subdir /var/log/radicale for the logfile.

Edit /etc/default/radicale to enable automatic start at boot.

Make a directory (filesystem) for the calendar and addressbook datastore:

mkdir /data/radicale
chown radicale:radicale /data/radicale

Edit the main config-file for radicale /etc/radicale/config

[server]
hosts = 0.0.0.0:5232
daemon = True
pid =
ssl = False

[encoding]
request = utf-8
stock = utf-8

[auth]
type = htpasswd
private_users = fred,dough,michelle
htpasswd_filename = /etc/radicale/users
htpasswd_encryption = crypt

[rights]
type = owner_only

[storage]
type = filesystem
filesystem_folder = /data/radicale/collections

[logging]
config = /etc/radicale/logging
debug = False
full_environment = True

Set the debug parameter to True during installation and testing to get more information.

Create a username-password file for radicale. This /etc/radicale/users and in the format of a .htpasswd file used by the apache-httpd. The htpasswd-tool is not installed as a dependency. By default radicale is only capable of using sha1 or crypt, so use the -d flag when using the htpasswd-tool.

dough:0123456789aBc
fred:0123456789Abc
michelle:0123456789abC

See this howto for using the better bcrypt http://evilshit.wordpress.com/2013/11/19/how-to-install-a-caldav-and-carddav-server-using-radicale/.

The client-config will be something like this:

For the calendar of Fred:

http://caldav.example.com:5232/fred/calendar.ics

username = fred
pw       = verysecret

For the addressbook of Fred change the url to:

http://carddav.example.com:5232/fred/AddressBook.vcf