Soulwinner
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451 4.4.0 primary target ip address responded with 421 4.2.1 unable to connect
MS exchange q Viewer gives this below message
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ASKER
@mas, exchange on Prem 2010 , we have O365 federation service
What SP / RU level are you at? You can find this by running the following Exchange PS command.
Get-Command exsetup | foreach {$_.FileVersionInfo}
Assuming this was a working environment, what, if anything, has changed? New ISP, new SmartHost, network equipment...etc..
Get-Command exsetup | foreach {$_.FileVersionInfo}
Assuming this was a working environment, what, if anything, has changed? New ISP, new SmartHost, network equipment...etc..
This may or may not be related but review the article and check the NIC settings on the Exchange server...
https://oddytee.wordpress.com/2016/08/16/exchange-server-message-queue-error-451-4-4-0-dns-query-failed/
https://oddytee.wordpress.com/2016/08/16/exchange-server-message-queue-error-451-4-4-0-dns-query-failed/
ASKER
the problem was with the SMTP port 25 on the firewall. Now its sorted
Belal should be award the points.
Agree with Todd,
Belal cleary explained about the port 25 block to check in post
Belal cleary explained about the port 25 block to check in post
ASKER
sorry guys :) thanks for your feedback
Please make sure your DNS working properly.
Please configure external for external lookup.