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Nieck-4588 avatar image
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Nieck-4588 asked ZhengqiLou-MSFT commented

Exchange Server mail flow routing issue

Hey,

At the moment I am with a customer who has two Exchange Server 2013 and two Exchange Server 2016 servers.

We want to create a send connector with one of the two Exchange Server 2016 machines as source. When created via the command below, Exchange tries to route the mail to the Exchange Server 2013 machine. Do you know a reason why the mail keeps routing to the Exchange Server 2013 machine?

New-SendConnector -Name OutgoingViaEOP -AddressSpaces testdomain.com -CloudServicesMailEnabled $true -Fqdn mail.example.com -RequireTLS $true -DNSRoutingEnabled $false -SmartHosts ***.mail.microsoft.com -TlsAuthLevel CertificateValidation -Usage Internet -SourceTransportServers ex16-1

office-exchange-server-mailflow
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That sounds normal with Shadow Copies
https://docs.microsoft.com/en-us/exchange/mail-flow/transport-high-availability/shadow-redundancy?view=exchserver-2019

Exchange 2016 and Exchange 2019 have the same improvements that were made to shadow redundancy in Exchange 2013: the Transport service on a Mailbox server now makes a redundant copy of any message it receives before acknowledging the receipt of the message to the sending server. Maintaining redundant copies of messages in transit is more than a best effort that may or may not work, because now shadow redundancy doesn't depend the sending server's supported features (support or lack of support for shadow redundancy doesn't matter). This helps to ensure that all messages in the transport pipeline are made redundant while they're in transit. If Exchange determines the original message was lost in transit, the redundant copy of the message is redelivered.

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Thanks for your reply. I don't think it's the shadow copy because it doesn't enter the shadow queue. The message is routed to the 2013 machine and then it hangs in the 'OutgoingViaEOP' queue with error code: 4.4.1 "Failed to connect. Winsock error code: 10060, Win32 error code: 10060." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts. The last endpoint attempted was xxx.xxx.xxx.xxx:25' FQDN=OutgoingViaEOP

We want to phase out the Exchange 2013 machines and therefore don't want traffic to go over this Exchange 2013 machine

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and the 2013 server is not the a source server for any send connector at all?

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ZhengqiLou-MSFT answered ZhengqiLou-MSFT commented

Hi @Nieck-4588 ,

Sorry but I just confused about the smart host you're using, is it a o365/ExchangeOnline smart host? I believe it is also the 4th question Andy asked.
And about the environment, is it a coexistence of Ex 2013 and Ex 2016 servers?

I think you should create the send connector on Exchange 2013 servers and specify the server FQDN or IP address as the smart host.
Create a Send connector to route outbound mail through a smart host
As you want to use the ex16 to route, you may use it's FQDN to add the smart host.

Best regards,
Lou


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Hi @Nieck-4588 ,

Do the suggestions above help? If the issue has been resolved, please click “Accept as answer” to mark helpful reply as an answer, this will make answer searching in the forum easier and be beneficial to other community members as well.

Regards,
Lou


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Hi @Nieck-4588 ,

It has been a long time since last reply, did these suggestions help you? If the above suggestion helps, please click “Accept as answer” to mark helpful reply as an answer.Your action would be helpful to other users who encounter the same issue and read this thread.

Regards,
Lou


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