External E-Mail tagging in Exchange Online

We all know the e-mail disclamer and “EXTERNAL” tags in subject lines that should make clear, that a specific e-mail is coming from external sender. Mostly this is done to make sure nobody clicks on links in external e-mails that might look like an external e-mail. This can easily be done by creating a transport rule in Exchange or Exchange Online that matches senders outside the organization. This rule adds something to the beginning of the subject line, and usually a preamble is added to the mail body.

Modify ProxyAddresses of Office 365 users without Exchange Online

As part of a Office 365 tenant rebuild, I had to move a custom domain to the new Office 365 tenant. The old tenant was not needed anymore, and the customer had to move to a Non-Profit tenant for compliance reasons. So the migration itself was no big deal: disable AzureAD sync change UPN of all users remove the domain connect the domain to the new tenant setup a new AzureAD sync assign licenses time for a beer That was my, honestly, naive plan for this migration.

Access to on-premise hosted Public Folders using Exchange Online mailboxes

Public Folders are still a thing. And while companies are moving their stuff into the cloud, Public Folders still need to be accessed by cloud-located mailboxes. Allowing the access from Exchange Online mailboxes to on-premise hosted Public Folders is well documented by Microsoft, but there are also some fuzz. I had to deal with this during a Office 365 transition project at one of my customers. The background The customer is running a single Exchange 2016 server in a Windows Server 2012 R2 forest.

Connecting to Exchange Online with PowerShell

The task was simple: Change the alias and the primary SMTP address of a Microsoft Teams team. This can be done by changing the alias and the SMTP address of the underlaying Office 365 group. But how? All you need is a PowerShell connection to Exchange Online. Patrick Terlisten/ Creative Commons CC0 All you need is a PowerShell on your local computer and Office 365 credentials with the necessary privileges.