I am looking to upgrade to Exchange 2007. We currently run a multi-site organisation. 1 back-end and 1 front-end (in DMZ) Exchange 2003 server in each site. We are the only site that is looking to move to Exchange 2007 so we will have to operate in a mixed environment for another couple of months.
When running Best Practices tool I am receiving “Exchange server cannot be accessed errors” for the front end servers in other sites in their DMZ, the firewall is blocking access.
My quesiton is can I ignore these errors as these are only front end servers with OWA running? If I install Exchange 2007 with no access to these servers will this cause routing issues overall?