Hi We have one site of windows 2003 with exchange 2007 SCC cluster, one HUB & CAS server and one Edge server, now we want to upgrade to exchange 2010 but this new setup we will do on another new site which does not have internet connectetivity (not internet facing site). druing our migration and coexistence of exchange 2007 and exchange 2010 can we install all our exchange 2010 roles mailbox, HUB and CAS on new site and keep all our existing live exchange 2007 servers roles in old site which is internet facing can edge server at old site can forward mails to users mailbox on exchange 2010 at new site or we have to put one server of HUB and CAS of exchange 2010 at old site with whcih has exchange 2007 servers roles. Thanks

When it comes to Hub Transport, you will not have to do anything. Exchange will route the email correctly for you between the servers. Just ensure that Sites and Services is setup correctly and the servers can see each other. However for CAS, if you want to access the server remotely, you will need an Exchange 2010 CAS role server in the site where Internet connectivity comes in. This is the traffic can be routed correctly. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.