No Internet Email To/From - Exchange 2003+2010 Coexistance w/ Barracuda Spam as Smart Host

Hello,

Overview:

Migrating from Exchange 2003 to Exchange 2010, with the use of a Barracuda Spam Filter appliance in between the Internet and internal mail server(s). All inbound/outgoing email gets scanned via Barracuda and is set up as a Smart Host in Exchange 2003. While 2003 is LIVE and operational, we've installed Exchange 2010 as a CAS, Hub Transport and Mailbox server all-in-one machine.

Exchange 2010 was left as-is with all of the default, out of the box Routing Groups, Send/Receive connectors created by-way of scanning through the current Exchange 2003 server and AD. The intent is to leave 2003 running as-is, and slowly migrate mailboxes over to the new system. Initially, we've created a test mailbox on the 2010 box to test email functionality inbound and outbound. Here are the findings:

* Email from 2010 user to itself: SUCCESS
* Email from 2010 user to a 2003 user: SUCCESS, but very long delay in the queue
* Email from 2010 user to an outside (Internet) address: FAILED
* Email from 2003 user to a test 2010 user: FAILED
* Email from outside (Internet) address to a test 2010 user: FAILED

After the initial Exchange 2010 installation and reboots, the Routing Groups were created and they are visible in Exchange 2003. They were located in the 'Exchange Administrative Group' and 'COMPANY_EMAIL' group. There were two of them. We are also using a multi-site Exchange environment to host/route/relay email for multiple company domains (i.e., @europecompany.com, @asiacompany.com, etc.)

We've followed many different tutorials and whitepapers on re-running the SETUP.COM /PreparePAD, /PrepareSchema, etc. to start anew and correct any issues that may have been lingering, etc. We're deleted and recreated new Routing Groups that are to link the Exchange 2010 to Exchange 2003 and Exchange 2003 to Exchange 2010.

* Is it accurate to have two bidirectional connectors (one in the Exchange Administrative Group and one in the COMPANY_EMAIL group) between two Exchange servers or a single 'bidirectional' connector? The method of understanding was that each Exchange server needs to have a connector to it and from it. Please correct us if this is wrong.
* Rechecking the Send and Receive connectors, this is the biggest concern and needs specific clarification by someone who's dealt with a Smart Host such as a Barracuda Spam filter in the middle:

--> Send Connector (one connector per hosted domain, i.e. @europecompany.com, etc.):
  * Address Space: SMTP and *.company.com (with Include all subdomains)
  * Cost: 1
  * Network: Route mail through the following smart hosts: [IP_of_Barracuda]
  * Not using External DNS Lookup settings on transport server
  * Smart hot authentication: None
  * Source Server: Exchange2010_Server

--> Receive Connector (kept the Default and Client connectors and have created an Internet connector):
  * Network: Using 'All Available IPv4' on port 25
  * Receive mail from remote servers: 0.0.0.0-255.255.255.255
  * Authentication: TLS, Basic, Exchange Server Authentication, Integrated Windows
  * Permission Groups: Anonymous User, Exchange users, Exchange servers, Legacy Exchange Servers

Concern #1: are the settings above at least close to what they ought to be?
Concern #2: When doing 'Get-RoutingGroupConnector', we do see the connectors listed for 'Exchange Routing Group' and 'COMPANY_EMAIL' group. Is there anything more that needs to be added for RG's?
Concern #3: For Send Connectors, for 'Route mail through the following smart hosts:', do we assign this with the Barracuda IP?
Concern #4: For Receive Connectors, do we specifically receive email from the Exchange 2003 server or directly from the Barracuda Spam filter?

Please assist us in figuring out where we stand as of the info above so we can proceed further with troubleshooting.

Thank you.