HiLet's say I have the following scenario in my E2003 environment:Internet > Exchange Bridgehead1 (Exch1)> Exchange Bridgehead2 (Exch2)> Exchange mailbox server (Exch3)So, emails from the internet need to transfer between two BH servers before reaching the destination mailbox server.My question is, when emails are only passing through a bridgehead server, and not actually delivered to a mailbox there, what processes does the message pass through? Does it stilll go through: Advanced Queue Engine > Awaiting Directory lookup queue > Message Cat > Messages waiting to be routed queue > Routing EngineOr is there another set of processes involved for mails just passing through a BH? And is this the same for the Hub Transport role in E2007?

Yes, that's true for Exchange 2003, detailed mail flow diagram can be found here... Exchange Message Flow http://technet.microsoft.com/en-us/library/bb123864(EXCHG.65).aspx Its different in Exchange 2007 since it doesn't use routing groups and uses Send/Receive Connectors, configuration of Active Directory sites and IP site links, you can see full detailed flow in component architecture poster... Exchange Server 2007 Component Architecture http://www.microsoft.com/downloads/details.aspx?FamilyID=FDCDF6E5-DE47-4B58-8086-282101BCDDE9&displaylang=en Amit Tank | MVP Exchange Server | MCITP: EMA | MCSA: M | http://ExchangeShare.WordPress.com