During a project with one of my customers, I was tasked to look at a non-delivery report (NDR) for a mail message. The bounce error was pretty confusing, but after reviewing the headers, we noticed that the DKIM check had failed. This was a bit of a surprise, because the message was sent from Microsoft … Continue reading "Field Notes: DKIM and missing selector records"
Last week an announcement was made: The native mail app in Apple's iOS has zero-day vulnerabilities, deemed critical. No patch is available at this time. More information about the vulnerability can be found here. For you as IT admin this means that you probably have work to do. The main questions you may be facing … Continue reading "Security Officer: Please block the iOS native mail app (for) now!"
On their security blog on the 3rd of June 2019, Microsoft announced that Valimail Monitor for Office 365 is available. This option enables organizations using Exchange Online from Office 365 for their company mail to leverage DMARC. The Road to securing E-Mail Cyberattacks are common these days. These attacks can be actively targeting your organization … Continue reading "Valimail Monitor for Office 365: Your Free DMARC Reporting Tool"
The issue During one of my Exchange Online migration projects I encountered the following error on several mailboxes: "Message : Error: Couldn’t switch the mailbox into Sync Source mode. This could be because of one of the following reasons: Another administrator is currently moving the mailbox. The mailbox is locked. The Microsoft Exchange Mailbox Replication … Continue reading "Exchange migration “Couldn’t switch the mailbox into Sync Source mode”"
As a consultant I do a lot of migrations or assist in them. In this case I wrote my own script for processing the information generated by the Mailbox Replication Service. This service is used in Microsoft Exchange on-premises and in the cloud for migrating the mailboxes between databases or environments. After multiple times doing … Continue reading "TOOL: My own Exchange Move Request Report script"
In this blogpost I want to address two real-life cases that I encountered in the same Microsoft Office 365 tenant. The reason why I address the two issues in this one blog is because the errors and steps to resolution, were identical for both issues. Background Information The issues occurred in a cloud-only tenant. The … Continue reading "The mysterious case of a failed account recovery and orphaned mailbox"