Hi We are running Exchange 2007 SP1. Our mail domain is @domain.com We have a sister organisation who are domain2.com. There is a VPN connection between the two networks. I understand for email between the two, it's possible to have mail either travelling via the public internet (i.e. using MX records) or to use a Smart Host and use the VPN. Would I be correct in thinking that for the latter, we would set up a Smart Host on a Hub Transport server for domain2.com and point it to the Hub Transport at domain2.com (they use Exchange 2007 too). Couple of questions: i) What would be the advantage of using a Smart Host as opposed to public DNS ii) On which Hub Transport would I actually set the Smart Host (we have multiple AD sites). Would it be all the Hub Transports, or the HT's that have an SMTP Connector to our 3rd party SMTP gateways? Many thanks!

I would think that since you are using a VPN, you would smarthost to the internal ip address of their HT rather than using public DNS and sending the messages across the Internet. Send Connectors can be scoped to a AD site, but they are org level objects so you can create just one and have all the HTs use it.More info:http://technet.microsoft.com/en-us/library/aa998662.aspx Send Connectors

Hi, I think you should first have a look at the connectors configurations on the link below. http://technet.microsoft.com/en-us/library/aa995965.aspx Smart are nothing but the direct IP address of the server (through VPN) where there is no dependability on MX DNS records. It can be the remote domain's third party Appliance or the Edge Transport server or ever Hub Transport Server. Since you have VPN connection btwn these domains, you should setup a SMART Host (Actually you have to setup a Send Connector) to directly deliver the mail to remote domain's HUB (check permissions on receiving HUB's Receive connector. Above article will help. check Receive Connectors Permissions Group) To answer your second question... Send Connectors are global where receive connector are per Hub Tx server. You have options either to select a single server to send mail to SMART HOST or have all HUB servers to send to a SMART HOST. You can select any HUB Transport server as SMART HOST in recipient domain which will take care of the delivery in multiple sites by its default connectors. Reference- Send Connector creation. http://technet.microsoft.com/en-us/library/aa998814.aspx http://www.petri.co.il/configuring-exchange-2007-send-connectors.htm Receive connector http://technet.microsoft.com/en-us/library/bb124327.aspx Hope this helps. Thanks.Vishal Ramnani | MCITP - Exchange 2007 | MCSE Messaging | MCTS - Win 2008 Config

Thanks both.However in relation to why we set up the Smart Host in the first place....what's the benefit of sending mails across the VPN over the public Internet? Effectively, both ways the mails are using the Internet anyway?

The VPN is encrypted though. ( Unless you are using SMTP over TLS).

Thanks Andy, so the fact that the tunnel is encrypted is the only advantage really? There is no difference in performance, reliability etc?

Well,SMTP is SMTP, so in that regard, there is no performanceor reliability difference. It makes iteasier for in some ways to use the VPN because it allows you toencrypt the traffic without doing anything different on the SMTP side. Your security and legal team would probably prefer you use the VPN as well. :)