Internal Send Connector Exchange 2016

We are migrating to Exchange 2016 from Zimbra and during migration we are setting up STMP address forwarding on the non-migrated exchange accounts so that a migrated account in exchange can still talk to an account on Zimbra.  I am trying to find a way for exchange to talk directly to zimbra without going through our mail gateway (which applies anti-spam and encryption policies) but regardless of the send connector configurations I've tried so far, it's still hitting the Internet Mail send connector.

So it should look like this - on exchange to on Exchange forwards to (zimbra alias) on zimbra
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Adam BrownSenior Systems AdminCommented:
Configure your root domain as an Internal Relay domain. Make sure your Mail Gateway sends mail to Exchange *first*. Then configure a send connector for your root domain so that it uses Smarthost delivery and set it to use the Zimbra server as the smart host. Make sure that send connector has the highest level of priority. Make sure that the non-migrated accounts *do not* have an email address with your root domain assigned to them (Otherwise this will fail), or just delete the mailboxes for unmigrated accounts altogether (preferred, unless your unmigrated users are using Exchange).

This type of configuration will cause Exchange to deliver messages for the root domain to the appropriate mailbox if the recipient's address is under its control. If the recipient email address doesn't exist in Exchange's environment, then it will send the message through the send connector.

I don't know how to get Zimbra configured properly for this, since I don't work with Zimbra, but the idea is probably pretty similar.

If you don't want to use this method, make sure the send connector for your Forwarding SMTP addresses is using the zimbra server as a smart host (A smart host is any SMTP server that doesn't belong to the same Exchange organization).

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MASEE Solution Guide - Technical Dept HeadCommented:
No comment has been added to this question in more than 21 days, so it is now classified as abandoned.

I have recommended this question be closed as follows:

Accept: Adam Brown (https:#a42043138)

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