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In the process of migrating from Exchange 2010 to Exchange 2016.
Currently Exchange 2010 is the Mailbox, Hub Transport, and Client Access server. Exchange 2016 is only a Mailbox server.
I want to verify mailflow between the 2 Exchange servers and currently it isn't working.
Current environment is like this:
Internet --> Sonicwall Email Security Virtual Appliance (spam smarthost) --> Exchange 2010
Exchange 2010 is working fine to send and receive emails that are external or mailboxes stored on its database.
However I cannot get Exchange 2016 to send emails externally (outside of the domain) or send emails internally (to mailboxes either on Exchange 2010 or Exchange 2016).
I checked the Message Tracking logs on Exchange 2016 and I see this error:
S:ItemEntryId=00-00-00-00-4F-AE-F9-BB-EF-20-ED-4B-B0-C6-7C-88-01-33-D1-DB-07-00-EE-FA-5A-AE-64-B2-A9-47-93-F1-13-72-CF-E6-C7-EF-00-00-00-00-01-0F-00-00-EE-FA-5A-AE-64-B2-A9-47-93-F1-13-72-CF-E6-C7-EF-00-00-00-00-19-F0-00-00;'S:DiagnosticInfo=Error: RetrySmtp, Diagnostic Information: Stage:UpdateMsgIdToPoisonContextMapping, SmtpResponse:451 4.4.0 DNS query failed. The error was: SMTPSEND.DNS.NonExistentDomain; nonexistent domain mailboxtransportsubmissioninternalproxy -> DnsDomainDoesNotExist: InfoDomainNonexistent, details:FailedRecipientCount:0; RetryRecipientCount:0';S:DeliveryPriority=Normal
I am not sure why Exchange 2016 cannot resolve the internal domain or external domains. In the IPv4 settings in the network adaptor the DNS settings are set to our domain controller and I am able to resolve and ping each Exchange server to/from each other so they are able to resolve and see each other on the network.
What other things should I be looking at to find out what's going on with the mailflow?
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Migrating from Exchange 2010 to Exchange 2016.
Currently, Exchange 2010 is the Mailbox, Hub Transport, and Client Access server. Exchange 2016 is just a mailbox server.
I want to check the mail flow between the 2 exchange servers and currently it is working from 2010 to 2016 but not working from 2016 to 2010.
Okay I have resolved the issue.
1) Had to update the DNS settings in the NIC on Exchange 2016 to reflect the same settings on Exchange 2010. This resolved the incoming email issue.
2) On our email spam appliance (Sonicwall Email Security Virtual Appliance) I needed to add the new Exchange 2016 FQDN to the source IP for the outbound MTA so mail flow would be allowed on that MTA for outgoing email.
Right now email is flowing to/from the Exchange 2010 to Exchange 2016 and email is also flowing to/from Exchange 2016 to the internet/domains outside of our network.
Glad to hear your issue has been resolved.
Have a nice day!
Cheers,
Lou
Hi @Quentin Roberts ,
Please check this doc: 451 4.4.0 DNS query failed Exchange Server error in message queue
If you have an external/alternate DNS server for your Exchange servers' NIC, you could remove it and then restart Microsoft Exchange Transport Service to see if it works.
Regards,
Lou
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Hello @Xzsssss
I updated the NIC DNS settings on the Exchange 2016 to reflect the same DNS settings on the Exchange 2010 and I am able to receive emails on Exchange 2016 now from mailboxes on Exchange 2010 and from email accounts external to the domain (such as Gmail). However I am unable to send any emails from mailboxes on Exchange 2016 to mailboxes on Exchange 2010 or mailboxes external to the domain (such as Gmail). I am able to send emails to mailboxes on the same Exchange 2016 host.
So the problem now is that I cannot send emails from Exchange 2016 to Exchange 2010 mailboxes or to domains on the internet.
In the Message Tracking log on Exchange 2016 I see 3 rows for each email I attempted to send but no errors, see below:
I just checked the Hub Connectivity logs on Exchange 2016 and I do see some authentication errors:
2021-05-06T12:46:15.388Z,08D910876F80C2FE,SMTP,default,+,SmtpRelayToConnectorSourceServers 4b4c782f-a43b-4d6b-9417-334084d1a32a;QueueLength=TQ=3;RN=3;.
2021-05-06T12:46:15.407Z,08D910876F80C2FE,SMTP,default,>,Exchange2010.domain.local[192.168.23.13]
2021-05-06T12:46:15.410Z,08D910876F80C2FE,SMTP,default,>,Established connection to 192.168.23.13
2021-05-06T12:46:15.414Z,08D910876F80C2FE,SMTP,default,-,Messages: 0 Bytes: 0 (Retry : Cannot achieve Exchange Server authentication)