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Edward CristFlag for United States of America

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Google and Office365 MX records on one DNS

I'm on Day #2 at my job here at the school district.

Scenerio.....

All students (5100) have only Google accounts...no problems

All staff have a Google account (lastname.firstname @[district].org)

and

Office 365 account (firstinitial+lastname@[district].org)

DNS has the MX record setup so that @[district].org goes to Google

BOTH 365 and Google emails use the same domain ([domain].org)

Can I setup my DNS to have 2 MX records pointing to Google and 365?

Is that a priority assignment setup?

My thinking is that when an email comes through that is the 365 address, the DNS will try to send it to Google first.  It will not find an address in Google. Then the DNS will go to the 2nd MX record and try sending it to 365.  Am I thinking correctly about messages and MX priorities?

Thanks!!!
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David Johnson, CD
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My thinking is that when an email comes through that is the 365 address, the DNS will try to send it to Google first.  It will not find an address in Google.so now google will send an NDR (non delivery reply)
Which genius though up this solution. Any idea of what their reasoning is/was?
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Oh gosh, David....as I said this is day #2 as the new Director of Technology....I'm still finding out where the bathrooms are!!!

I'm trying to keep things going until we turn off 365 for email.

Thanks
I can think that I know why the older director is no longer the director (hopefully didn't get promoted)
It clearly doesn't work and the decision was made to standardize on Goggle workplace..
can you login to the office 365 portal and check your licensing type i.e. A3 for Education.. this included office applications for the desktop  (Microsoft Office 365) for up to 5 devices per license. So who needs Microsoft Office?
Google workplace is $4/student OFFICE A1 is free, and A5 for teachers which included office products is $8CAD/month
Can I setup my DNS to have 2 MX records pointing to Google and 365?

You can physically, but it is not a good idea. Think about emails showing up on multiple servers. It would be havoc.

Both Google and Microsoft have failover built in.  If you have a reason to use both, then you can use Google Workspace for domain.org and Microsoft for subdomain.domain.org but you would want to have a good use case for that.  In M365, your account is based on the domain, but that does not mean you need to use Exchange.



My thinking is that when an email comes through that is the 365 address, the DNS will try to send it to Google first.  It will not find an address in Google. Then the DNS will go to the 2nd MX record and try sending it to 365.  Am I thinking correctly about messages and MX priorities?
No, this thinking is not correct.

Exchange on-line (or on-premises) does not use the MX for the messaging domains that it managed. It does not use MX but only its global address list. If a corresponding email is found (locally), the message goes directly to this mailbox.

Google does probably the same thing.

You have to configure connectors and forwarding (using specific domains used by Google and Microsoft) to redirect messages on the other side, if necessary.

So, it is not a good idea to configure MX for the 2 messaging systems. Because, all messaging systems will treated all non existing emails as bad emails with NDR.

Folks

The ship sailed way before I arrived....we're moving all staff to Google and turning off their M365 emails soon.
Looking to keep both working and getting folks their messages until we decide the process to get their M365 messages to their Gmail accounts.

I appreciate your input....thanks.   
Is this a migration?  We may have missed what you are after.  
Well.....for months now, the staff have had 2 email accounts....M365 and Google.

I want to get to a place where we stop the M365 accounts and go exclusively Google.

But the staff have been using M365 more than Google...so I need a plan to get them over to Google without giving up access to their M365 inbox/folders.

Here's what I think

If the account is the same on both platforms there's nothing you can do :)

Now,
If there's one account on one and another account on the other that differs even by a letter you can work with that .

You need to set up the mail flow as :
MX with priority 0 to O365
And then configure the domain as Internal Relay on O365
and finally set up a connector to the google account :)

basically that's something you can also do the other way but Idk if Google (gmail has something similar).

PS: Just read your last comment,so.... Please make your statement on what you want to do :) because is still not clear.

Email is probably going to both anyway.  I think you could just remove the M365 mx record and just stick with Google's. Before doing that, set up an alias for each staff member so their Workspace account continues as lastname.firstname @[district].org and the alias would be firstinitial+lastname@[district].org. That way there is no issue with receiving email from fristinitial+lastname@.

Part of the switch may include migrating email from M365 to Google.  https://support.google.com/a/answer/180898?hl=en

There used to be a more clear path to migrate in Google's admin console which was there the last time I did a migration, after checking my own console and looking at the instructions, there are some changes.

Once the mx is removed for Microsoft, the exchange portion will no longer receive or send email but you would still log in to Microsoft was  firstinitial+lastname@[district].org for MS apps or office.com and onedrive/sharepoint.
You asked, "Can I setup my DNS to have 2 MX records pointing to Google and 365?"

Can you? Yes.

Should you? No.

Well... you'll only setup 2x MX records to have a debugging nightmare.

MX records work by priority, meaning 100% of all mail flows to whichever MX of highest priority or in the case where multiple MX records have the same priority, fastest MX to respond wins... then mail flows to the winner...

This means having MX records point to multiple places can "technically be done" + what a nightmare trying to figure out where email actually delivered.

Also you have the problem of if the non-Gmail MX wins, then it's unlikely your non-Gmail MX server will accept *@gmail.com email, so all this mail will bounce instantly.
Best practice - Only have 1x MX record ever setup, unless you sync messages between MX records somehow to keep all MX servers in sync.

With only 1 MX record, if you must reboot the machine or take the MX down for maintenance, the SMTP protocol (sending MTAs) will simply see the outage, then reschedule message for a resend in the future.

So in most cases having only a single MX record defined is best... certainly easiest to debug + maintain...
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Edward Crist
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