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Dave StoneFlag for United States of America

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New MX Records

Hello,
We have just switched our internet connection from cable to fiber. This required a public IP address change. I updated the MX records with our domain host but I am now getting  442 4.4.2 Connection Dropped  errors. Not all mail is doing this but a significant amount. I have several iPhone users who are now not getting mail on their phones but other iPhone users do. I realize it takes a little while to propagate the servers with the new records but it has been over 6 hours. Any help with this would be appreciated.

Thank you
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Todd Nelson
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Thank you. Yes, NAT was updated. I guess you are right. Patience has never been one of my virtues.
You can change the TTL on your records to force faster update across the web but without this they can take a long time to replicate.
Hello, All the online tools for looking up mx records and reverse dns show correctly now. However, mail is still staying in the Exchange queue. Do I have to do anything on the Exchange server like stop and start the transport or something?
Can you perform a successful telnet outside of your network from the Exchange server?  You might need to install the Windows telnet client on the Exchange server.

telnet outlook.com 25

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If not, then the firewall or ISP is blocking outbound SMTP traffic.
The firewall logs show no blocking and I can mail to some domains almost immediately, such as yahoo.
Any NDRs?

I'm assuming Exchange here...

Run this command to see what the errors (if any) are associated with the messages in the queue.

Get-Message | ft -auto DateReceived,FromAddress,Subject,LastError

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It may be a lot of info posted to the console, so you can run this command to export the data to a CSV file.

Get-Message | SelectObject DateReceived,FromAddress,Subject,LastError | Export-Csv C:\MessageQueueErrors -NoTypeInformation

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I can't see all the output from the first command. the second returned an error, "The term 'SelectObject' is not recognized as the name of a cmdlet, etc..
Sorry... Use "select-object" instead.
Yes. It shows me the same thing the message queue shows. a bunch of 421 4.4.2. connection dropped errors.
How is outbound mail flow configured for your environment?

Exchange >> Smarthost >> Firewall >> Internet?
Exchange >> Firewall >> Internet?
Exchange >> Firewall >> Smarthost >> Internet?

Do you have some sort of content filter between Exchange and the external recipients?

I'm going to ask again ... Can you perform a successful telnet outside of your network from the Exchange server?  Don't check from the firewall.  Check from the Exchange server.
Thank you. It was actually the firewall configuration.