Hello all, I have a client with the following (hope this is the right location): Site 1 in the US - Exchange 2007 Site 2 in latin america - Exchange 2010 Both sites connected via IP Sec VPN Both sites are on the same domain and manage the same .com addresses. Only difference is that the 2010 server has their latin america users on its database and the 2007 has the american users. Client wants the following but I am not sure its possible : Both sites to be able to fall back to eachother if one goes down. (If US exchange server goes down, automatically the 2010 will route emails properly and vice versa) Both sites to only show their local users in the GAL (North Americans only see North Americans and Latins only see Latins) So, is this a pipe dream or is it doable? What would be needed if there are additional items needed?

Hi, This is not be possible (correct if I'm wrong someone) as the clustering technology is different in E2k7 and E2K10. If your client want this to be working then I would suggest to migration the US site to Exchange 2010 and then use the CASArray/DAG features for DR. Else, each site is on their own.

Hi, Only allowing users to view users in their local region sounds like Address List Segregation (http://technet.microsoft.com/en-us/library/bb936719(EXCHG.80).aspx) but that will not work in a mixed environment, as per the caution in the article: "Do not complete the steps in this white paper in a Microsoft Exchange Server 2010 environment. If you try to apply these steps in an Exchange 2010 environment, significant issues may occur, and it may not be possible to resolve these issues." So, as I see it you will need to get both servers running Exchange 2010 (at SP2) before you can use Address List Segmentation and you will need to create a DAG to provide failover/DR options, but (and it's a big BUT) this assumes your WAN link is fast enough to keep up with the Log Volumes you expect to replicate per day - you will be able to calculate this using the MBX Storage Calculator. Edit: Here's a link explaining GAL segmentation in Exchange 2010 SP2. http://channel9.msdn.com/Events/TechEd/NorthAmerica/2011/EXL326 Cheers Dave Disclaimer: The opinions expressed and/or postings on this site are my own personal opinions. They do not represent or reflect the opinions of my employer.