If you haven’t already done so, you can enable ‘External’ tagging in Outlook for your Microsoft Office 365 tenant. This allows any external emails to be tagged which can be helpful if someone tries to impersonate emails or for attempted Phishing emails.
Resource: Set-ExternalInOutlook (ExchangePowerShell) | Microsoft Learn
Quite simple to enable:
- Connect to Exchange Online using Powershell
Connect-ExchangeOnline -UserPrincipleNameuser@domain.com
- Check status
Get-ExternalInOutlook
- If set to false, to enable
Set-ExternalInOutlook -Enabled $true
- To exclude a domain from being tagged:
Set-ExternalInOutlook -AllowList “example.com”
- To exclude an email from being tagged
Set-ExternalInOutlook -AllowList “admin@example.com”
