GMail and exchange dual delivery

[jhaigh]

Hi,

I am currently trying to configure dual delivery with exchange and gmail and have run into an issue that won't allow me to send email from an exchange mailbox to an alias google sub domain.

 

I have successfully validated our primary domain with google and set up an alias sub domain (g.mydomain.co.uk) which receives email from other email addresses without issue however when I send an email from within our exchange organisation I get a #554 5.4.4 SMTPSEND.DNS.NonExistentDomain; nonexistent domain ## error from our exchange server.

 

Anyone have any ideas what the issue might be? I have tried adding accepted domains and a send connector in exchange but it doesn't make any difference.

 

Thanks in advance

[kmount]

Can you resolve the g.mydomain.co.uk from your internal DNS? (typically see this if someone has mydomain.co.uk as an internal DNS zone and forgets MX records)

[jhaigh]

No cannot resolve g.mydomain.co.uk internally and yes we have mydomain.co.uk as an internal zone. So do I need to add an internal MX record for g.mydomain.co.uk pointing to the google MX servers?

[ZeroHour]

No cannot resolve g.mydomain.co.uk internally and yes we have mydomain.co.uk as an internal zone. So do I need to add an internal MX record for g.mydomain.co.uk pointing to the google MX servers?

Yeah pretty much.

[kmount]

Yep, or instead of having the full domain.co.uk zone internally consider using more specific ones like http://www.domain.co.uk and intranet.domain.co.uk so "unmatched" entries rely on your DNS forwarders (upstream DNS). (whereas what is happening now is unmatched entries return null because well, there's nothing there)

 

If you have a long list of entries in your mydomain.co.uk zone you probably want to just go ahead and add the g.domain.co.uk mx record to match what you did for your public DNS.

[jhaigh]

Thanks for your help so far.

I am now able to send to a g.mydomain.co.uk email address from within the exchange organisation however my issue now is I have created a test gmail account that doesn't have an exchange mailbox and I can send to it using the g.mydomain.co.uk email alias from anywhere but I cannot send from the test account back to an exchange recipient using the primary mydomain.co.uk email addresses and I cannot send to it using the primary domain mydomain.co.uk.

Hope that make sense.

 

Any ideas?

 

Thanks

[chaplic]

I'm not entirely 100% I follow that description but I thinks it's an internal relay/ authoritative domain quesiton.

 

By default, in exchange if [email protected] doesn't exist (because it's in gmail) then exchange will say 'recipient doesn't exist'. You need to change that domain to 'internal relay'. This means, if you send to [email protected] and it doesn't exist in exchange, it will attempt to send it elsewhere over whatever route it can find.

 

however, you do not want to do the same in gmail (to allow [email protected] to sent to [email protected]) as non existant email addresses will end up looping.

 

This feels a bit like a 'wouldn't start here' problem, what is your actual goal?

[kmount]

Condensing what you wrote to confirm - you cannot send from [email protected] (gmail) to [email protected] (exch) yeah?

 

Do you get an NDR back into Gmail, and what does ECP say about the mail on Exchange side?

[ZeroHour]

Basically you are not doing dual delivery but split delivery (dual is mail is sent to both johnsmith@emailserver1 and johnsmith@emailserver2)

You need to create a contact in exchange with the [email protected]domain address for it to route to the other address. You can also setup exchange to be an internal relay rather than authoritative with a smart connector to gmail's server but in the interim you may want to create the contact. Both methods need a contact to me created tbh.

[jhaigh]

My goal at this stage is to remove student emails from exchange and create gmail accounts for students. Would it be better to create these mailboxes using a subdomain configuring their primary email address as student.mydomain.co.uk rather than trying to create an alias to the main domain?

 

These are the NDR/errors I get:

Sending from my exchange address to test school gmail account (using primary domain mydomain.co.uk) #550 4.4.7 QUEUE.Expired; message expired ##

Sending from my exchange address to test school gmail account (using g.mydomain.co.uk) Now working ok after creating internal mx record.

Sending from school gmail test account to my exchange email ([email protected]) you are not in mydomain.co.uk error.

Sending from personal gmail account to school test gmail account (mydomain.co.uk) Not received

Sending from personal gmail account to school test gmail account (g.mydomain.co.uk) works ok.

 

Thanks so far.

[chaplic]

OK, there's a few ways to do this. Here's one

 

In exchange, create a mail enabled contact which has your desired address of [email protected] and target address of [email protected]

 

In Gmail, create a account with mail forwarding (do not keep) for [email protected] forwarding to [email protected]

 

Your SPF records will have to include gmail and office365

[jhaigh]

So I am now revisiting this issue after doing some other summer jobs and I have made a bit of progress.

I have created the exchange mail contact for a student as chaplic suggests above and can now send to this gmail test student account using test [email protected] from an exchange user however when I try to reply to this email from within gmail I get the following error:

554 5.7.1 [email protected]: sender address rejected: you're not in mydomain.co.uk

 

Any ideas how I can get around this?

 

Thanks

Edited August 14, 2018 by jhaigh

[chaplic]

Progress!

 

I’m not the strongest on gmail but I think you can create a user without mailbox (essentially the same as a contact) and set and auto forward using the tennant address - so [email protected]

[jhaigh]

A little progress:-)

Just had a look at that and email is a mandatory field so I am guessing that's not possible.

I am wondering if there is a setting in either exchange or my ISP dns settings that will allow emails with the same domain name that are essentially coming from google servers i.e. outside the exchange organisation to be accepted?

[chaplic]

You cannot do anything in DNS/ isp to have what you want. You must point the mail to a single system and configure that up to route how you want.

 

Entering the email address is fine, we are basically saying ‘accept email and then forward it on’

 

However, it looks like google suggests a thing called split delivery

 

https://support.google.com/a/answer/2685650?hl=en.

 

Which will also achieve it and if it’s their preferred route, so much the better

[Simcfc73]

I'm currently running a hybrid install of Exchange with a split delivery where the studetns accounts live on Google.

 

Split worked fine with accounts on my exchange box but when they are migrated to the cloud they fail with unknown account. I'm having to create mail contacts for all students, I've tested this on one account and as soon as I create the contact mail flow begins (although I am still gettting an error in Outlook saying the adress is no longer valid)

 

Not sure if I will still need to do this when i decomission my Exchange box.

 

Only got exams results to go out tonight so all is fine.

[jhaigh]

The issue I am having is sending email from gmail back to exchange where the staff member only has an exchange mailbox. I have been playing around with settings in advanced routing in gmail but it's still not having it.

 

According to this article it should be possible:

 

https://community.spiceworks.com/how_to/38537-ms-exchange-and-google-apps-split-delivery-for-single-domain-name-k-12-school-sample-shown

[chaplic]

I am certain it is possible. I have a spare gmail and o366 tennant, if you can hold on about 2 weeks I will setup, if you have not solved already.

[jhaigh]

Any help appreciated.

 

I can't help thinking it is something to do with exchange thinking that the email is illegitimate as it is essentially coming from an email address (@mydomain.co.uk) which is the main exchange email domain but from outside the exchange organisation i.e. from google servers. Authentication?

[chaplic]

That’s the size of it. As a default Both gmail and exchange have a directory and will look that up to see if the mailbox exists, and if it doesn’t then nondeliver the email.

 

In exchange (under mail flow I think, currently sat by a pool and missus might get upset if I whip out my laptop 😀) we can change the domain type to be ‘internal relay’ instead of ‘authoriative’ which basically says ‘hey, if you cannot find a mailbox for this email then just send it thru whatever route you know’. I don’t think there is an exact equivalent in gmail.but you wouldn’t want to set it because anyone sending an email to typo@yourdomain would cause a mail loop.

[Simcfc73]

That’s the size of it. As a default Both gmail and exchange have a directory and will look that up to see if the mailbox exists, and if it doesn’t then nondeliver the email.

 

In exchange (under mail flow I think, currently sat by a pool and missus might get upset if I whip out my laptop 😀) we can change the domain type to be ‘internal relay’ instead of ‘authoriative’ which basically says ‘hey, if you cannot find a mailbox for this email then just send it thru whatever route you know’. I don’t think there is an exact equivalent in gmail.but you wouldn’t want to set it because anyone sending an email to typo@yourdomain would cause a mail loop.

 

Thats how mine was setup.. but when you go to hybrid i changes.

 

The connectors are created in O365 to talk to the onsite exchange server, if it doens find the contact it drops it.. you can't change the connector type. Still can email Google on the exchage box, just not migrated mailboxes.

[chaplic]

I don’t mean connector, assume you are talking about the ‘outbound to guid’

 

Mail flow-> accepted domains

 

Will list all domains. Pick the domain in question and change to internal relay

[MarilynH]

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