Office 365 Hybrid Deployment - Mail Loop

If you're ever in the middle of an Office 365 Hybrid deployment, you've configured everything correctly but you notice that when you're testing the mail flow from one premise to the other, it's causing a continuous mail flow (you will receive a NDR), the first thing I would suggest you look into is whether there's a gateway in the middle of your on-prem Exchange and your Office 365 environment.

Office 365 Hybrid is only supported if you have nothing between your on prem Exchange, and the O365 environment.  That means no IronPorts etc getting in the way.

I recently encountered an issue where there was a continuous mail flow symptom.  Office 365 was trying to deliver the email to on prem Exchange, it was caught up in the IronPort and then it tried to deliver it back to Office 365.  To get around this I opened Exchange up to the internet by NATting Port 25 on a different WAN IP which would bypass the IronPorts entirely.  I amended the Connectors in Office 365 so they'd connect through that address, rather than through the IronPorts.

Once this was done, the issue resolved itself immediately.

Create new AD User with Remote Mailbox | Office 365 Hybrid

I recently had a client who had a Hybrid Office 365 who required a set of users to be created, and Office 365 mailboxes created at hte same time.  Whilst I could have had a script to create the users, then go through and add mailboxes to them, I decided that it would be better to smash it all in one hit.

Thanks to my colleague Gareth for writing this script

The following process is comprised of two steps.

1. Run a script that references a CSV File
2. A CSV file that has all the relevant information in it

In this case my CSV file had the following:

The BackupEmail was put there at the Client's request.  It was just an area to put the user's personal email address within the AD object.  

The script used is the following, which needs to be saved as CreateUsers.csv.  Note the bold areas which are the variables that have been included.

$Users = Import-Csv -Path "C:\Userlist.csv"

$OU = "OU=Sub-OU,OU=Parent-OU,DC=DOMAIN,DC=com,DC=au"     

foreach ($User in $Users)           

{           

    $Displayname = $User.Firstname + " " + $User.Lastname           

    $UserFirstname = $User.Firstname           

    $UserLastname = $User.Lastname           

    $SAM = $User.Username         

    $UPN = $User.Firstname + "." + $User.Lastname + "@domain"        

    $Password = "<insertpassword>" 

    $Mobile = $User.Mobile

     $remoterouting = "smtp:" + $UPN

     $Notes = $User.BackupEmail

    New-ADUser -Name "$Displayname" -DisplayName "$Displayname" -SamAccountName $SAM -UserPrincipalName $UPN -GivenName "$UserFirstname" -Surname "$UserLastname" -AccountPassword (ConvertTo-SecureString $Password -AsPlainText -Force) -Enabled $true -Path "$OU" -ChangePasswordAtLogon $false –PasswordNeverExpires $true -MobilePhone $Mobile -HomePhone $Notes

    Enable-RemoteMailbox $SAM -RemoteRoutingAddress $remoterouting

}

Save the script as well as the .csv file into the same location, then run the script through Exchange Management Shell.

This will create the user account and will also create the Office 365 Mailbox which can be viewed from either Exchange On Prem, or the O365 Tenant.  Remember that it takes a bit of time for Azure AD Connect to sync all the AD objects as well.  It might help to force an Azure AD Connect sync.

The last step you will need to do is to assign an Office 365 license to that particular user, or users.

Don't worry though, I've got that covered in a previous blog post.

Microsoft Exchange could not discover any route to connector CN=Windows SBS Company Web Connector [SERVERNAME]

Recently when I was troubleshooting some Exchange issues on a client's server, I noticed the following Event log and thought I would troubleshoot it further:

What's happening is that a 'Foreign Connector' is still present in the Active Directory and Exchange configuration for an old SBS environment (SBS was recently decommissioned).  This is for SharePoint email to web feature, which was never used and it's not needed.

To get rid of this, it's safe to just delete the connector.  To find the connector, type the following:

Get-ForeignConnector | fl

To delete the connector, type the following:

Remote-ForeignConnector "Windows SBS Company Web Connector SERVERNAME"

This will remove the orphaned connector, clean up the errors and stop them from occurring.

SMTP rejected a (P1) mail from 'HealthMailboxXXXX.

Recently a client of mine noticed that their Exchange server (Exchange 2013) was getting an event log every five minutes saying the following:

There was no interruption to mail flow, but we wanted to look into it and find out why it was happening.  I had a look into this event and it looks like there was an issue with this Health Mailbox.  Having a look into what the best cause of action is, it was understood that these can be deleted from AD without any issues.

I logged into the DC and deleted the specific user account in question:

After deleting this user account (and I had made sure the Active Directory Recycle Bin was enabled), I restarted the Microsoft Exchange Health Manager service.  If needed, this will re-create the HealthMailbox.  After monitoring for about half an hour, I was happy that the event was no longer showing up within Event Viewer.