We use an appliance from Clearswift to scan all inbound/outbound e-mail for a variety of things. One feature it offers is to sync with the e-mail LDAP as part of it's anti-spam, by only allowing registered e-mail addresses.
Right now I maintain that list manually.
Am I able to query the Zimbra LDAP to get a return of valid e-mail addresses? Can someone point me in the direction of the correct LDAP query to issue?