I would like to know if the followin setup is supported or notI have two exchange servers in two different forests with trust enabled -one way.Domain1 with Exch2010Domain2 with Exch2k7is this supported or do we need to have exch2k10 on domain2 too?thanks.

Hi,I've answered this in your other thread, but for historical purposes i'll add here.You will have to explain further what your ultimate goal is, but yes Exchange 2007 and Exchange 2010 in two Forests with a trust is supported and both can succesfully provide the other with a linked mailbox.If both plan on having the same primary SMTP namespace however you will run into Autodiscover issues, however free/busy will remain unaffected.OliverOliver Moazzezi | Exchange MVP, MCSA:M, MCTS:Exchange 2010, BA (Hons) Anim | http://www.exchange2007.com | http://www.exchange2010.com | http://www.cobweb.com |

Here's a good TechNet article on Cross Forest boundaries with Exchange 2010."Understanding Multiple-Forest Permissions" http://technet.microsoft.com/en-us/library/dd298183.aspxOliverOliver Moazzezi | Exchange MVP, MCSA:M, MCTS:Exchange 2010, BA (Hons) Anim | http://www.exchange2007.com | http://www.exchange2010.com | http://www.cobweb.com |

You will need a 2 way trust!!!The above mentioned configuration is supported and ensure you have the E2K7 server with SP2 installed.