Hi Running Exchange 2007 SP2. Multiple AD sites, each site has its own Hub, CAS and Mailbox server. Of all the sites, only HQ has Hubs that relay to the SMTP Gateways. Our mail domain is contoso.com We would like to bring in an application server for SiteA that can accept email from Exchange and send email to Exchange. Toplogy: Outlook > Exchange > Application Server (users sending email to Application Server) Application > Exchange > Outlook (Application Server sending email to users) Only SiteA will have this application and only SiteA users will use this application. Some questions: 1. In order for the Application server to send emails to Exchange, I assume we need to create some Receive Connectors. Would we create these on the Hub Transports in SiteA? 2. If we wanted to create the Receive Connectors first, but not have them being used for mail routing, can we set the cost to high (cost = 100 for example)? 3. In order for Exchange to send to the Application server, I assume we need to create Send Connectors. This is a global setting isn't it, unlike Receive Connectors which are per Hub Transport? 4. The Application Server *may* use the same domain name as Exchange, but have addresses like application1@contoso.com, application2@contoso.com. How would we set this up seeing as contoso.com was also being used by Exchange? Any other points would be appreciated.

1. Yes create a dedicated receive connectors for applications, copiers etc if you don't already have one. If you already have one for applications just add this IP into the remote network settings of the connector. Allowing application servers to relay off Exchange Server 2007 http://blogs.technet.com/b/exchange/archive/2006/12/28/3397620.aspx 2. The connector is already scoped to allow only the specific IPs to relay through it, not sure what you would accomplish by restricting them "mail routing" which you can't really do. Please explain further. Questions 3 and 4. You need to set up smtp namespace sharing, then set up the corresponding send connector to the application server. When you do this, if someone sends to app1@contoso.com, Exchange gets it, sees that there is no user with that address and then relays it to the connector. Use the steps below, it's the same for 2007. Configure Exchange 2010 to Route Messages for a Shared Address Space http://technet.microsoft.com/en-us/library/bb676395.aspx James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Thanks James. Some further questions: 1. Am I correct in thinking that Send Connectors, i.e. configuring Exchange to be able to send to this application server, are global settings, even though we can configure specific Hubs to be involved? 2. Am I correct in thinking that Receive Connectors, i.e. configuring Exchange to be able to receive messages from this application server, are configured per Hub Transport? 3. If the existing Default Receive Connectors on the Hub Transports in Site A are configured to receive email from ANY IP address, does this mean we don't need to create extra RC's? 4. Regarding authentication, on the Default Receive Connector for the Hub in Site A, I can see that: Authentication is set to TLS, Basic, Exchange server and Integrated Windows Authentication - so how would the application server authenticate with the Hubs? Does it actually need to authenticate? Permissions groups are set to Exchange users, Exchange servers, Legacy Exchange servers only, - in which case, what do we need to check to allow the external application server tobe able to use this connector?