Microsoft Small Business Server Post-Migration Issues with Microsoft Exchange

Just wanted to write about a couple issues that I’ve seen occur after migrating customers from Microsoft Small Business Server to Microsoft Server 2012 R2 (with Essentials Experience role), with Microsoft Exchange 2013 On-Premise.

Migration documents that were available were used at the time of migration. We still observed these issues after following. Please note that since these issues occurred, migration documents may have been updated.

Just an FYI: I provide Small Business Server Migration and consulting services. For more information, click here!

Windows SBS Company Web Connector ServerName

After the migration was complete we started seeing event logs pertaining to a “Windows SBS Company Web Connector ComputerName”, often mentioning it’s referencing an object in the Deleted Items container, also referencing the connector is not being activated due to no routes available.

Event ID: 5016

Microsoft Exchange could not discover any route to connector CN=Windows SBS Company Web Connector SERVERNAME,CN=Connections,CN=Exchange Routing Group (XXXXXXXXXXXXXXXXX),CN=Routing Groups,CN=Exchange Administrative Group (XXXXXXXXXXXXXXXXX),CN=Administrative Groups,CN=First Organization,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=domainname,DC=local in the routing tables with the timestamp 3/5/2016 1:55:34 PM. This connector will not be used.  Total source server count: 1; unknown source server count: 1; unrouted source server count: 0; non-active source server count: 0.

What is happening is that a “Foreign Connector” is still present in the Active Directory and Exchange Configuration for the SBS environments SharePoint e-mail to web feature. In my client’s environments SharePoint is no longer used, so it is safe for us to delete this connector. Only delete this connector if you know you’re not using it (it is used for SharePoint e-mail to web feature).

To list and get information on the orphaned connector, open Exchange Powershell and run:

Get-ForeignConnector | Format-List

To delete the orphaned connector, enter the following command in Exchange Powershell and update the connector name to match the name shown in the command above:

Remove-ForeignConnector “Windows SBS Company Web Connector SERVERNAME”

This will remove the orphaned connector and clean up these errors from occurring. You can also remove the connector using ADSIEDIT, however I prefer to use ADSIEDIT as a last resort, and find this method not only easier, but cleaner.

SMTP rejected a (P1) mail from ‘HealthMailboxHEXHEXHEXHEX@domain.local’

Initially post-migration we started observing this event on the server. Mail flow was not affected and everything was functioning properly.

Event ID: 1025

SMTP rejected a (P1) mail from ‘HealthMailboxXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX@DOMAIN.local’ with ‘Client Proxy EXCHSRVR’ connector and the user authenticated as ‘HealthMailboxXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX’. The Active Directory lookup for the sender address returned validation errors. Microsoft.Exchange.Data.ProviderError

Additionally, on our corporate firewall (that provides anti-spam), we would observe numerous undeliverable bouncebacks on outgoing messages to the e-mail address “inboundproxy@contoso.com” with the subject “Inbound proxy probe”. These messages occur on exact 5 minute intervals continuously.

Using Exchange powershell to view the active Health Mailboxes, we see that each of these bounce backs are being stored on a particular health mailbox. Essentially the mailbox will continue to grow. Due to the growth, this issue needs to be resolved so the mailbox doesn’t continue to grow in size.

Numerous things can cause this, however in our case looking at transport logs, it is seen that a HealthMailbox is sending e-mail to another HealthMailbox but using an incorrect e-mail address. The Health Mailboxes on the Exchange server have “domain.com” e-mail addresses, while according to the transport logs, the e-mails are being sent to “domain.local”.

Something got mixed up, either with provisioning the Exchange E-Mail address policies, or the domain configured as “default domain”. Either way, Exchange is configured and running, so I wanted to correct this in a manor that would have minimal consequences or changes to the system.

To correct this issue, we need to go in to ADSI edit and modify the “ProxyAddresses” value for the HealthMailbox. Note that any type of mailbox can have numerous aliases and a single default alias. Inside of ADSIEdit for “ProxyAddresses” the value/format is case-sensitive, and uppercase SMTP configures default e-mail address, while lowercase smtp configures alternative aliases. An example value: “SMTP:alias@domain.com” for default, or “smtp:alternative@domain.com” for an alternative alias.

Identifying the account from the event log (note the XXXXXXXXXXXXXXXX in the example), we found the account in the Monitoring Mailboxes container inside of ADSIEdit. We right-clicked on the specific HealthMailbox account, went to properties, and found the “ProxyAddresses” value. We then proceeded to create a new alias by clicking edit, using lowercase smtp and created “smtp:HealthMailboxXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX@DOMAIN.local” and added it to the list, we did not modify or delete any existing values. All we did is create an alternative alias.

So now the Health Mailbox is receiving e-mail for both “@domain.com”, and “@domain.local”. Immediately the bounce-backs stopped, and event logs disappeared.

PLEASE NOTE: For this fix to work, you MUST confirm that the issue is due to the domain .com and .local mismatch. I’m not quite sure, but this issue may also occur after changing the default domain, or default e-mail address policies, in which case you still could use this technique to resolve the issue.

Hope this helps some of you, cheers!