Mail working with no DNS found?

Question

I think I need to learn something new. I moved a domain from an old hosting co. to google workspace, both the name registration and the hosting. The email started working, stuff coming in. I waited a day or two for name propagation and for any dns, google's or others, to resolve the domain. None of them do, still days later. But I can send an email to ******@thatdomain.com and it gets to google servers and gmail. I thought that was impossible without dns resolution. What am I missing? I've set up MS servers many times but never Exchange, so maybe you all know the trick? Thanks.

Answer 1

Hi @Tom Cantlon

To me in normal cases it is not possible without DNS resolution.

You may need to update the public MX record at your domain registrar (now Google) to point to the current email service provider (Google).

To check the MX record, you can use some online tools like https://mxtoolbox.com/.

(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)

While if you have no MX records, the email would be delivered to the host thatdomain.com. (based on RFC 5321)

And if thatdomain.com has an A or AAAA record pointing to a server which can handle SMTP requests, the email can still be delivered successfully.

(But to me this doesn't apply to your situation)

But I can send an email to ******@thatdomain.com and it gets to google servers and gmail.

What email service are you using to sent from?

Would it be possible that you have some internal MX records or you have configured Google workspace as smarthost in your email service/client?

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Answer 2

Kael Yao, thanks for a lot of good info. To answer your last question, no, don't have internal MX records or google as smart host. I'm sending out through my 3rd party hosting company but there have been many emails that have come in from new people and old clients who used to send to us at the old host. So it seems anyone could email to ******@domain.com and succeed. I asked google help about it and they just gave me steps for creating forwarding from domain.com to www.domain.com which they said would show up in dns. They don't have a normal dns control panel so a little hard to tell the details. But now domain.com does resolve on any dns. That means I can't test it anymore. I can't re-break it just to test because that would interrupt people. So everything is working but I'm still baffled how mail could reach us when no dns was resolving our domain. A mystery for another day. Thanks.