Category Archives: Transport

General troubleshooting steps for inbound/outbound mail flow issues

Mail flow can be stopped for various reasons in a organization. Also it depends entirely on the environment design as there are various factors involved in affecting the mail flow like network, ports , firewall , antivirus , anti-spam , transport agents , directory services , connectors misconfiguration , exchange server services not running up and the list goes on.

Its always better to design the mail flow architecture  in a easy understandable way and also we need to ensure that the SMTP security inbound\outbound is tightened in the perimeter level to make sure no spam emails are circulated.

In this article i have mentioned few basic troubleshooting steps that can be followed during mail flow issues in a environment

This applies for both inbound/outbound mail flow issues

Following things can be done

1) First run EXBPA to check if we get any misconfig errors ( applies only for exchange 2007/2010). You can skip this step if you are running Exchange 2013 and upcoming versions.

2) Go through your event logs on hub transport if its 2010 , Mailbox Server if its 2013 to see if we get any clue (at times it may be a back pressure as well so its better to check logs). Its better to check all the exchange services at this time  and ensure if they are running.

3) Do a telnet from internal to external network and see if everything is fine and also perform telnet test from external domain to your domain.This test will usually help you to identify if there is any SMTP traffic block in your firewall.

Below is the example of performing a telnet test

Type Telnet domainname orIP 25



Above is an example of successful delivery to the target domain.

4)  Check whether the MX record is valid for the affected domain.

Below is an example of performing mx validation for domain.

5) Enable protocol logging both send and receive connectors and see if you are able to track anything.

6) Check if  the connecting IP is in  blacklist

We need to obtain the following tool to do the check:

If there is a blacklisting, please contact the providers of Blacklist. They will take a look into the reason behind blacklisting and remove the domain from the blacklist for you.
7) Check for NDR message.Enable message tracking for those  nondelivery mails and see if you get where the message gets dropped.This will help you a lot to identify the problem.
8) Analyze  Message header of the NDR to see in which hop the email was dropped.
9) Check the send connector and receive connector config and make sure the settings are correct according to your environment setup.
10) Check your firewall config and make sure port 25 inbound/outbound are open. Also check if there is any  SMTP filtering in your firewall which will be the culprit in most of the cases.
Hope this article is helpful in troubleshooting mail flow issues.
Thanks & Regards 
Sathish Veerapandian
MVP – Exchange Server 

Customized system messages to users in different languages in Exchange 2013

In this article let’s have a look at customizing system messages (Warning mailbox limit, ProhibitSendMailbox, DSN) to users in different languages.

Let’s take an example if we have users who are using mailboxes across different regions in multiple geographical locations. In this scenario users will be having different languages as default according to their region. For example user might have his default language as French and some might have default language as English.

In these scenarios we can customize this system message according to different region so that the users will be getting the system generated emails according to their regional language.

Let’s take a scenario of customizing system messages for French users as well as English users who are residing in different locations.

So we need to deliver DSN,Quota Messages in English for SetA users and in French for SetB users. By this way SetA users gets the DSN in English and SetB users gets DSN in French.

In-order to accomplish this task we need to create a new customized quota message. We need to run the below commands.


First we need to set the language property of the user mailbox according to his region. In order to accomplish this we need to run the below commands

For French users – Set-Mailbox – identity “user” -languages “FR-CA”

For English users – Set-Mailbox – identity “user” -languages “EN-US”

1) Warning Messages

For French users

New-SystemMessage –QuotaMessageType WarningMailbox -Language FR –Text “type French text here”


For English users

New-SystemMessage –QuotaMessageType WarningMailbox -Language EN–Text “Watch out! Your mailbox has reached its maximum capacity


2) Prohibit Send mailbox:

New-SystemMessage –QuotaMessageType ProhibitSendMailbox –Language EN –Text ““type english text here”

New-SystemMessage –QuotaMessageType ProhibitSendMailbox –Language FR –Text “type French text here”


3) Prohibit Send receive mailbox:

New-SystemMessage –QuotaMessageType ProhibitSendReceiveMailbox –Language FR –Text ““type French text here”

New-SystemMessage –QuotaMessageType ProhibitSendReceiveMailbox –Language EN –Text “Watch out! Your mailbox has reached its maximum capacity”



4) For DSN’s we can use the below command

New-SystemMessage -DsnCode 5.3.2 -Language En -Internal $true -Text “Any English TEXTMessage”

New-SystemMessage -DsnCode 5.3.2 -Language FR -Internal $true -Text “Any French TEXTMessage”

Once after we have made the above changes users will be able to receive system messages according to their MailboxRegionalConfiguration settings.


To view the system messages we can use the below commandlets:

To view the language for user – Get-MailboxRegionalConfiguration –Identity username

For Warning – Get-SystemMessage -Identity EN\WarningMailbox

For prohibit Send – Get-SystemMessage -Identity EN\ProhibitSendMailbox

For prohibit SendReceive – Get-SystemMessage -Identity EN\ProhibitSendReceiveMailbox


To modify system messages:

Set-SystemMessage -Identity EN\WarningMailbox -Text “Your mailbox is becoming too large.”

Set-SystemMessage -Identity EN\ProhibitSendMailbox -Text “Your mailbox can not send nor receive any more …”

Set-SystemMessage -Identity EN\ProhibitSendReceiveMailbox -Text “Your mailbox can not send nor receive any more …

To remove any customized system message you can use the below command

Remove-SystemMessage -Identity EN\WarningMailbox.

Refer more:

Sathish Veerapandian

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