Routing messages from O365 to a domain.local

Question

Hello everybody.

we have a Domain.local running on Zimbra which is used for the temp personnel.. lot of users who change frequently during the year.. we don't want to give them a full O365 license because we don't have so much license. and anyway they change so frequently which make the whole thing not worth..

All the other full time employee already are on O365 using a multitenant infrastructure. We have an exchange hybrid.

Is there any way I can create route/connectors so that the user on the Zimbra server can send and receive email to/from the O365 users which are on the public domain?? may be via the Exchange hybrid?? I believe i can create an SMTP relay to send from ZImbra to the O365, but what about the other way??

Answer 1

Hi @mariora ,

You can set up your hybrid environment to send and receive emails from Zimbra. To do this, you must set up an email contact in Exchange Online with the primary SMTP for domail.local, and you must also set up domail.local in the Hybrid Configuration Wizard.
The link below can help you with more details. In the link the reference to domain.local is an Application Server. Think of it as your Zimbra.

https://practical365.com/mail-contact-object-affecting-outgoing-smtp-relay/

(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)

Regards,

Kllin Nunes

Answer 2

Hi @mariora ,
You can create two connectors according to the method in the following article, one is “A connector from Microsoft 365 or Office 365 to your own email server” and the other is “A connector from your own email server to Microsoft 365 or Office 365”. Please refer to: Set up connectors to route mail between Microsoft 365 or Office 365 and your own email servers

Have you considered deploying your employee mailboxes in on-premsies Exchange? I noticed that you have deployed a hybrid environment, HCW will automatically create a connector between the on-premises Exchange and Office 365, and encrypt the communication between the on-premises Exchange and Office 365. And through the local AD, you can better manage your on-premises Exchange mailbox.

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Answer 3

I like Kllin idea.. it's perfect for my needs. also found a probably better way for me to work that way.

I have lots of email in the domain.local and cannot create for each one a mail contact, but yesterday trying to do something I found that if I create a Transport rule on O365, i can intercept every email sent to a specific domain, like domain.local, and route them to a connector that can send to a SmartHost. I tried with a maildemon server which is like ZImbra at the end and it works like a charm.

Using the method described in the article I should be able to use as the SmartHost the hybrid Exchange (so can use also TLS), and from there with a second connector send to ZImbra.

For the other way around I just need to setup the SMTP relay on the Hybrid server and should be done.

Will try to put all together and will let you know.