route ougoing mail to external server for local users

In Exchange System Manager - Admnistrative groups - Routing Groups - [Site Name] - Connectors, create a new SMTP connector to forward all mail to the other server.

Sorry do you mean Send Connector in Exchange 2007?

My knowledge is of Exchange 2003, but the principle should be the same.

Sounds like you will install an another exchange server onto a new domain and then you will migrate all the users.

If it would be the same organization you all the exchange servers that are creating the same uses the same GroupRoutingConnector.

In order for your scnerio to work, you should first create a two way trust between domain controllers (this because it will be easier to migrate users onto another exchange server which resides within a new domain)

You create a new SMTP connector under the following: Exchange Management Console -> Organization Configuration -> CAS -> Send connector -> here create a send connector and set this send connector to use a smart host, set the smart host IP address of the "old" exchange server that resides within the "old" domain)

You should also configure "relay" access within the exchange servers. This can be done under -> EMC -> Server Configuration -> CAS -> Receive connectors

Thanks for the reply but I don't understand what you mean with "If it would be the same organization you all the exchange servers that are creating the same uses the same GroupRoutingConnector"

Also I forgot to mention before is that on the "old" server I host several domain and it is only one of them that will migrate to the "new" server.

I have already redirected the MX records so incoming mail are going to the "new" server but when users from this domain e-mail each other the e-mails never leave the "old" server they are internally routed and that is what I want to change, I want these particular users to do the following, when userA send an e-mail to userB (both are from the same domain/org) that message will be received by the "new" server.

Thanks!

Since they are exchange servers on different domains you can ignore what i said regarding the routingroupconnector.

In your comment, where is userA and userB located ? Are their mailboxes within the "old" exchange server (in the old domain?) or are their mailboxes within the "new" exchange server (in the new domain?)

UserA and UserB are located in the "old" exchange server. These accounts have been created from scratch on the new server aswell so when UserA send a message to UserB, UserB at the "new" server will receive the message.

So the users have one user account and one mailbox on each site ? Lets call them for site A and B, am I understanding this correct ?

yes that is correct

I take it that your end plan, is to migrate the one"domain" to the new exchange server.

As this "new" exchange server is located within the new domain, i would create a two-way trust between the domain controllers in respective domain forest and have a user in site A, to map up his mailbox in the new exchange server (this can be done thru the two way trust),

If you dont want to do this, you can do the following.
For all the users who will be on the new exchange server:
1. create an external contact for the users in the "old" exchange server
2. set the forwarding smtp address to the new exchange server
3. add the external contact to the users mailbox (in the old exchange server) to make a copy and forward it to the external contact (in the old domain)

so the mail flow is: mail to user (in old exchange server) -> user has a forwarding to an external contact -> external contacts mail forwarding address is the name of the exchange server in the new site) -> a email copy is sent to the same user in the new exchange server

I would rather not setting up mail contacts for forwarding as I would have to set it for each user. Thanks for the idea though..

Isn't a way to just route internal mail externally, to tell exchange to handle internal mail as if they were external mail that need to go through the MX records to find their path.

Can't this be done in Exchange 2007? I think this was possible in Exchange 2003.

Just to summarize,

Well it depends of MX records, domain names, certificate names, accepted domains.

Do you two seperate forests ? Also I was under the impression that you want a message that was sent for user (userA), that hes/hers mailbox should get this message in bouth the "old" and "new" exchange server ?

I must admit im a little bit confused what your trying to accomplish and why

Yes it is a bit weird the way we are trying to to this migrate but that is what we were told to do.

Yes, they are two completely separate forest with no connection between them whatsoever, well besides the internet off course.

Both "old" and "new" servers have the accepted domain for the domain let's call it bongo.com BUT it is only the "new" server that receives incoming mail since the MX record points to this server.

Can it be that having an accepted domain for bongo.com on the "old" server prevent internal mail being treated as external mail?

so when a user who is on the old exchange server sends a mail to userb@bongo.com, the mail goes only to userb@bongo.com in the old exchange server and not at all to the new exchange server ?

Also you wish to have this email sent to bouth the mailbox on the old exchange server and the new exchange server ?

Yes, exactly.

I'ts not important that emails be sent to old server only to the new one.

Thanks for the information Bes, I undestand your scenario now.
This somewhat complicated to do if not impossible, I've never heard of anyone who would want this or anyone who've done this as well.

As a workaround would it be possible for you to set a forwarding (to the new exchange server) on the respective mailboxes that are going to be migrated ?

Bes,

whats the status regarding this ?

Alright, just following up,

cheers!

This is not the solution I wanted but it worked as a workaround, not sure if what I wanted to do is even possible since no one came up with a solution.
Thanx to JuusoConnecta for tryin to help.