CalDAV auto discovery is the process in which given only an username and a password a CalDAV client is able to retrieve the server that serves username's domain and any URLs required to retrieve calendar collections. The auto discovery process is a combination of DNS SRV or TXT queries followed by the retrieval of a number of HTTP well known URLs and finally by a set of PROPFIND commands that are used to compute calendar collections.
The DNS configuration is described in RFC 6764 - Locating Services for Calendaring Extensions to WebDAV (CalDAV) and vCard Extensions to WebDAV (CardDAV).
A minimal DNS configuration might look like this:
DNS SRV records for CalDAV auto-discovery:
The rest of the auto configuration process (retrieval of well known URLs, etc) is automatically handled by Axigen and no configuration is required.
CalDAV Auto Discovery in eM Client
eM Client uses a different mechanism when performing auto-discovery for CalDAV services.
This mechanism is controlled via the Axigen CLI and it involves a couple of parameters:
enableWebDavAutodiscovery– controls if Axigen advertises CalDAV/CardDAV services when queried by eM Client
webDavAutodiscoveryUrl– this is the URL that is sent to eM Client; it is usually set to match the Axigen WebMail URL, e.g. something like
Axigen CLI configuration for eM Client auto discovery: