(FAQ) What is the ActiveSync Auto-Discovery Service?
What is the ActiveSync Auto-Discovery Service?
Auto-Discovery allows users to set up an ActiveSync account with just their email address and password, without needing to know the host name of the ActiveSync server. The Auto-Discovery service requires Webmail to listen on HTTPS (443).
For most systems, it also requires that a new CNAME or A record be added to DNS. 'autodiscover.domain.com' should resolve to the server running ActiveSync.