GMAIL HELP! APPEND HEADER TO FORWARDED EMAILS?

[Koldov]

Any GOOGLE WORKSPACE/GMAIL gurus in here?

 

As we've moved to GMAIL our old O365 tenant is forwarding emails from the old accounts for a period of time.

 

It's been a while now but I've just looked at the stats and it's still a pretty impressive amount. I've sent emails to remind users they should be updating and contacts/suppliers/websites with their new email addresses, but you know how it is...

 

Admittedly, a lot of it might be spam or phishing so it might not be actually getting though at the GMAIL end, or they are emails that the recipient just isn't bothered about.

 

It could be that they've forgotten all about it already and aren't even looking to see where the email has actually been sent to, but I thought I could make a rule that would append a header to say that it has been forwarded.

 

To save me floundering about in the GMail menus (if that's where it should go), if it's possible can anyone give me a step-by-step instruction please on the easiest way to do this?

 

I though it would be GMAIL > Content Compliance:

 

1. Email messages to affect = Inbound

 

2. Add expressions that describe the content you want to match (If any of the following match) = oldemaildomain.com

 

3. If the above expressions match do the following = Add custom headers

 

Bit lost here on 'X-Header Key : Header Value'

 

or

 

Prepend the custom subject?

 

or

 

'Options'... Address lists

 

Only apply this setting for specific addresses/domains... and create a list somewhere with just the old domain on??

[Koldov]

Anyone?

 

[LeMarchand]

Our "html" rule uses the "Subject" field.

 

[Koldov]

Thanks, that's great. So I'm on the right track at least!

 

Anyone know what I'm looking at setting in terms of section 2?

 

"2. Add expressions that describe the content that you want to search for in each message

 

If ANY of the following match the message

 

Expression

 

Add expression"

 

I'm looking at 'Advanced Content Match' then I need to add a location, possibly one of these choices out of that list...

 

Full Header

 

Sender Header

 

Envelope Sender

 

Then 'Content to look for' = oldemaildomain.co.uk

 

Then Section 3. If the above expressions match, do the following

 

'Subject > Prepend the custom subject' = "THIS MESSAGE WAS FORWARDED FROM YOUR OLD EMAIL ACCOUNT!"

[jthompson]

I'd have thought that the messages you want to match will have been sent to the old domain, not from it? If that's the case, you' may need to match against "Any envelope recipient" rather than envelope sender.

[andy_b]

Would you not add the old domain to GOOGLE WORKSPACE/GMAIL and then setup aliases? This is what we would do if moving to Office 365.

[jthompson]

Would you not add the old domain to GOOGLE WORKSPACE/GMAIL and then setup aliases? This is what we would do if moving to Office 365.

 

Would advise considering that, too. A bit of setup but it softens and solves your problem for good, and gives everyone an easier time of it.

[Koldov]

I'd have thought that the messages you want to match will have been sent to the old domain, not from it? If that's the case, you' may need to match against "Any envelope recipient" rather than envelope sender.

 

Haha I have no idea, that's why I'm asking!

 

Yes, sent to the old O365 domain and then 'sent' from that domain/forwarded to the new GMail account. It's not a transparent thing, the old domain actually receives the email and sends it.

 

On a test email in GMail, clicking on the drop down next to the To: shows amongst other things...

 

from: [email protected] - via - olddomainco.onmicrosoft.com

 

to: [email protected]

 

and

 

mailed-by: olddomain.co.uk

Edited November 9, 2023 by Koldov

[Koldov]

Would you not add the old domain to GOOGLE WORKSPACE/GMAIL and then setup aliases? This is what we would do if moving to Office 365.

 

Would advise considering that, too. A bit of setup but it softens and solves your problem for good, and gives everyone an easier time of it.

 

Possibly, but the migration was set-up by a 3rd party consultant and I didn't have anything to do with it (only cleaning up the mess). Are you saying somehow adding a Microsoft O365 domain into Google Workspace and making all Google accounts with the O365 address as an alias would mean emails sent to O365 would then go to Google....?

 

I'm sure I haven't even scratched the surface of what Google can do as I've only just started to look into it in any depth, but at the time the Head wanted it done yesterday (as we already had Google Workspace set-up in a basic form for distance learning over lockdown), so the consultant said just do a migration of emails and set-up forwarding for a month or so...

 

Also, they were quite insistent that after that time the old O365 domain be into the ether, so maybe this was an easier way than adding domains and aliases and then, removing domains and aliases from all the accounts...? Or they didn't even know it was a possibility...

[jthompson]

Yeah, so I think you'll be wanting to match your old domain in "Any envelope recipients" for incoming emails.

 

Prepend the subject with [olddomainname]. Nothing too cumbersome since it'll get included in any replies/forwards that people send thereafter.

[jthompson]

Also, they were quite insistent that after that time the old O365 domain be into the ether, so maybe this was an easier way than adding domains and aliases and then, removing domains and aliases from all the accounts...? Or they didn't even know it was a possibility...

 

Possibly that was felt to be the 'cleanest' solution? As long as you control the old domain name and can update its DNS and MX records, you can add it to your Google tenacny as a domain alias. When you do that, Google will give you a wizard spelling out exactly wha DNS changes you need to make, and will confirm that it's set up correctly, etc. Every user in your Google tenancy will then automatially get an alias with that other domain, so that emails to their old addresses will arrive in their Gmail mailbox as normal.

 

You won't need to do anything on the 365 front I don't think. 365 will simply stop seeing email arrive, so you can leave that old domain attached to it no issue. Plenty of schools have the same domain name registered with both platforms.

[andy_b]

Possibly that was felt to be the 'cleanest' solution? As long as you control the old domain name and can update its DNS and MX records, you can add it to your Google tenacny as a domain alias. When you do that, Google will give you a wizard spelling out exactly wha DNS changes you need to make, and will confirm that it's set up correctly, etc. Every user in your Google tenancy will then automatially get an alias with that other domain, so that emails to their old addresses will arrive in their Gmail mailbox as normal.

 

You won't need to do anything on the 365 front I don't think. 365 will simply stop seeing email arrive, so you can leave that old domain attached to it no issue. Plenty of schools have the same domain name registered with both platforms.

 

Bascially this, with the added bonus that when you click reply you aren't sending it to yourself (which they are potentially doing now?).

[jthompson]

And in case management still want the old domain killed off, you can kinda do that by adding rules to quarantine or reject emails sent to it, whilst retaining the option not to should the need arise!

[Koldov]

Ah, thank you that explains it then!

 

No, we don't control the DNS of the domain for the O365 tenant, it was set-up by a 3rd party Learning Platform company (quite bizarrely in my opinion) that all local schools had a .schoolname.schooltypetown.co.uk address.

 

So, for example I had [email protected] and someone else had a [email protected], there was also @schoolname.juniortown.co.uk, schoolname.infanttown.co.uk, domains so each school had a sub-domain of 'their school' and the TLD was 'schooltypetown.co.uk'.

 

All very strange and glad to be out of it in some ways, but now it all the administration and management falls on me alone... I'd got quite proficient at O365 after badgering them for admin access to Entra/Azure (because their support dwindled off to being pretty dismal as most of the other schools had left), but now all of a sudden we're on Google... and I've got to learn everything from scratch and expected to be proficient from day one!

 

Hooray?

[Koldov]

Bascially this, with the added bonus that when you click reply you aren't sending it to yourself (which they are potentially doing now?).

 

No, although I get your logic, strangely enough by some magic it appears to only reply to the original sender...

[Koldov]

Just for completeness... and for future reference when I've forgotten all about it...

 

I tried 'Any envelope recipients' and it didn't work**, so I chose 'Location: Recipients header' in the end and 'Contains text: olddomain.co.uk'.

 

Anyway, it seems to have done the job!

 

**Maybe because it's SMTP forwarding and not Inbox forwarding? Also I thought I'd seen the envelope and sender can be different, so maybe if I'd put the onmicrosoft address in as it's sent 'via' that, maybe that's what is in the envelope?

Edited November 10, 2023 by Koldov