I'm responsible for transitioning an organization from 100% native E2K3 to E2K7. I've had little time to learn the differences and have adeadline to get the first servers installed within the week. My mainconcern isthat the company's AD site design does not resemble the E2K3routing groups. Assume one 2007/2003 routing group connector to oneE2K3 routing group that has11 mailbox servers in10 different AD sites. All E2K3 mailboxes will be consolidated on one E2K7 clustered Mailbox server. Will have 2 Hub Transport servers as SOURCE servers on connector.Does it make sense to add all11 E2K3 mailbox serversas TARGETservers on the 2007/2003 routing group connector?I'm hoping this will ensure thatall messages will be delivered from the Hub Transport servers directly to each recipient'smailbox server. Thanks in advance to anyone/everyone who takes the time tothink about this and respond.

how you specify E2k3 target servers depends how you want mail to be routed, other factors to consider is how is your WAN layout and E2k3 server routing topology look like. You only need one target server for this to work but i would specify at least 2 for redundance and load balancing.

The hub transport servers will be at the center of ahub-spoke network.The E2K3 servers are all in different AD sites, but one E2K3 routing group.I know that at least 2 target servers is recommended for redundancy. Is there any reason not to add11target servers (all in the same E2K3 routing group)?Will thisalways route from the Hub Transport servers directly to the E2K3 recipients' mailbox serverwithout going through another E2K3 server first.In a 100%E2K3 I thinkthat bifurcation is done on theHub Transport server and then the bifurcated copies are route to eachmailbox server for delivery. I'm just not sureif the same will happen when there is amessage formultiple recipients on multiple E2K3 servers. If it does, thenwouldeachbifurcated copy transfer through the 2007/2003 connector directly to the appropriate mailbox server?

if you add all E2K3 server as targets is more of management/administrative issiue than techincal (for example message tracking between the to system does not work), mailflow will work either way. You will as you say skip a mailhop if make it this way, also remember that you should also change the connector going from E2K3 to E2K7 and add all E2K3 servers as source servers to enable direct mailflow from all E2K3 server direct to E2K7 hub servers. dont forget to disable linkstate propagation on E2K3 servers for a more predictrable mailflow. http://msexchangeteam.com/archive/2006/11/01/430185.aspx http://www.microsoft.com/technet/prodtechnol/exchange/guides/E2k3TransnRouting/93366a5b-cab0-4e4e-8f8f-66282c3dafd7.mspx