You need to update an on-premise Exchange to forward all company email to an external mail service (e.g., a hosted Exchange, Google Apps).
This is done via a Recipient Policy. You do not need to do this per Exchange account, but for an entire email domain with Exchange. In this example, we’ll redirect all mail on the internal Exchange server for the domain puryear-it.com to an outside mail service.
- Log on to your old Exchange server as an admin and run the System Manager. Expand Site Name > Recipients > Recipient Policies
- Right-click on the “Default Policy” and select Properties; switch to the “E-mail Addresses (Policy)” tab. In the example below, there are 2 domains configured, @puryear-it.com and @puryear-it.local, with the former being the “primary” (i.e. address that mail sent from those users will appear to be from).
- Uncheck the box next to the public domain you’re moving. If it is bold (as above), you’ll need to make a different domain the primary. In this case, the primary domain was the public @puryear-it.com, which we want to move so I’ve made @puryear-it.local the primary domain and removed @puryear-it.com for the policy. Click OK to save the changes.
- If you get a warning like the one below about updated all corresponding recipients, click “Yes”.
- Back in the System Manager, expand Site Name > Connectors. Right click on “Connectors” and select New > SMTP Connector.
- Name the connector something reasonable (in this case, the name of the domain I’m moving), check “Forward all mail through this connector to the following smart hosts” and enter the name of the hosted Exchange’s SMTP server. Click the “Add” button and select the local Exchange server as the bridgehead.
- Switch to the “Address Space” tab. Click the Add button.
- Add a new SMTP address space.
- Enter the domain you’re moving in the field and leave the cost as 1. Click OK on both windows to return to the System
- You should see the new connector in the list.
- That’s all there is; the Exchange server will no longer deliver mail for that domain locally. If you send a message through the local server now, it should be routed out to the hosted Exchange.