Hello,I have an exchange 2007 server with public folders enabled. I also have a third party (Zimbra) mail server solution on site which can synchronize free/busy data with Exchange by utilizing the F/B repository in public folders. One of the steps calls for me to use the Add-AvailabilityAddressSpace command to define the Zimbra SMTP domain as if it were a separate forest. This works just fine with the test Zimbra server. Here's my concern. The production Zimbra SMTP domain is the exact same name as our Exchange default SMTP domain. I'm afraid that if I add this name as an "external forest" that it will screw up my Exchange users ability to see one another's local free/busy data, or it won't bother to look in the public folder at all because it thinks it's local to exchange.Can anyone tell me if this will cause a problem, or will Exchange simply look for a 2007 mailbox first for the free/busy data, and then if it can't find one, look to the Public folder repository for the synchronized free/busy data?So, to clarify, both systems have default email addresses set as @company.com Can I specify @company.com in the Add-AvailabilityAddressSpace command even though the Exchange server itself uses @company.com for its default email addresses.Essentially what I'm hoping it will do it check to see if the free busy data exists in the 2007 Availability Service, and if it doesnt, check the Public Folder F/B folder.thanksChristiaan

I haven't tested this scenario - only Forests with different Namespaces.I know in a Resource Forest model if your primary SMTP address space is the same Autodiscover fails, so with this methodology of thinking I would be pretty sure using the Add-AvailabilityAddressSpace will barf when you try and add the same address space..OliverOliver Moazzezi | Exchange MVP, MCSA:M, MCTS:Exchange 2010, BA (Hons) Anim | http://www.exchange2007.com | http://www.exchange2010.com | http://www.cobweb.com |

Hi, When querying the free/busy for the attendees, the Availability service uses Active Directory to resolve the user's mailbox version. If the mailbox version is not Exchange 2007, the Availability service uses the user object's legacyExchangeDN attribute to retrieve the Free/Busy information in Local Public Folder. If the mailbox is hosted on Exchange 2007, the Availability service uses XSO to open the mailbox and query the calendar to get the requested free/busy data. Thus, the SMTP domain for the two organization is not related to the Free/Busy. And also not break the Exchange 2007's free/busy to be retrieved smoothly. Thanks Allen