Hello, I would like to know if anyone has experience of sharing calendars and free busy information to another exchange 2007 organisation in a seperate forest? The forests may be untrusted or if required a trust mauy be made. Is this possible or would we need to implement Exchange 2010 CAS and use MS Federation Gateway? Rafa

Hi, Here is a paragraph I read: "In Exchange 2007, you could share calendar data with other Exchange 2007 organizations. Doing so meant that your CAS servers had to talk to their calendar servers, and the controls around it were not that granular. In order to do it, you either needed to establish a forest trust and grant permissions to the other forest’s CAS servers (to get detailed per-user free/busy information) or set up a separate user in your forest for the foreign forests to use (to get default per-org free/busy data). You also have to fiddle around with the Autodiscover service connection points and ensure that you’ve got pointers for the foreign Autodiscover SCPs in your own AD (and the foreign systems have yours). You also have to publish Autodiscover and EWS externally (which you have to do for Outlook Anywhere) and coordinate all your certificate CAs. While this doesn’t sound that bad, you have to do these steps for every single foreign organization you’re sharing with. That adds up, and it’s a poorly documented process " http://blogs.3sharp.com/deving/archive/2009/08/21/some-thoughts-on-fba-part-2.aspx It points off to this topic about the Availability service. http://technet.microsoft.com/en-us/library/bb125182.aspx To make free/busy available, you should ensure the autodiscover service is working fine in the Account Forest. http://msexchangeteam.com/archive/2008/02/13/448127.aspx After the autodiscover is avaiable in the Account forest, the free/busy request can be sent to the Availability Service which can access each calendar folder of the mailbox to get the free/busy. For free/busy information between domain, u can deploy Federation server, detail Ripu Daman Mina | MCSE 2003 & MCSA Messaging