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Exchange not delivering emails to .com

Dan
Dan asked
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I currently host my own exchange 2016 server internally.   I currently have a .org domain.
I just created a new DNS lookup zone of .com for the same domain, both internally and externally, in external DNS.

I also added under exchange, under accepted domains, the new domain.com, but I'm still not able to receive emails externally.

Internally, I can send from my .org email to my .com email, and works fine, but just doesn't work when I send an email from my gmail to my .com email address.

Can anyone point me in the right direction?
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Jason CrawfordTransport Ninja

Commented:

Have you updated the MX record in external DNS for domain.com?

DanNetwork Engineer

Author

Commented:

yes, I configured the MX record as @ to point to my //mail.mydomain.org 


Transport Ninja
Commented:

Run an inbound SMTP test through ExRCA:


https://testconnectivity.microsoft.com/

DanNetwork Engineer

Author

Commented:




Attempting to send a test email message to dan@mydomain.com using MX mail.mydomain.org.
  Delivery of the test email message failed.
 
Additional Details
 
The server returned status code 550 - Mailbox unavailable. The server response was: Relay not permitted
Exception details:
Message: Mailbox unavailable. The server response was: Relay not permitted
Type: System.Net.Mail.SmtpFailedRecipientException
Stack trace:
at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, Boolean allowUnicode, SmtpFailedRecipientException& exception)
at System.Net.Mail.SmtpClient.Send(MailMessage message)
at Microsoft.Exchange.Tools.ExRca.Tests.SmtpMessageTest.PerformTestReally() in d:\dbs\sh\utff\1225_145035\cmd\2b\sources\Dev\bpa\src\ExRCA\Tests\Smtp\SmtpMessageTest.cs:line 70
Elapsed Time: 787 ms.


DanNetwork Engineer

Author

Commented:

i have to leave for the night, I will be back in the morning.

Jason CrawfordTransport Ninja

Commented:

Ditto

DanNetwork Engineer

Author

Commented:

I think I need an RDNS entry with my ISP for //mail.mydomain.com to point to my //mail.mydomain.org IP address, right?

Jason CrawfordTransport Ninja

Commented:

You're referring to a PTR record and yes your ISP would edit that.  Do you have an external email server you can send from so you can run message tracking inbound?  I'd be happy to if you want to PM me

DanNetwork Engineer

Author

Commented:

My exchange server is inhouse, internal, not external.  :(


I think I just configured my firewall correctly, I'm just trying to think what else I might need to do?


DanNetwork Engineer

Author

Commented:

I got it resolved.  I also added the mail,mydomain.com to my firewall to accept those emails.

I also created a new network on my firewall with a new IP address, and pointed the external DNS to it.

Then I called my ISP, and had them create the reverse DNS pointer, not sure if that helped or not.


I did my last test and it's working now.   Thanks for your help.

Jason CrawfordTransport Ninja

Commented:

Glad I could help.  Take care :)