How to enable reject direct send in exchange online?

Hey there! I actually set this up for my organization last month. To enable "Reject Direct Send" in Exchange Online, you need to use PowerShell - it's not available in the admin center GUI unfortunately.Here's what worked for me:1. Connect to Exchange Online PowerShell using the Connect-ExchangeOnline cmdlet2. Run this command: Set-TransportConfig -RejectDirectSend $true3. Verify it worked with: Get-TransportConfig | fl RejectDirectSendWhat this does is prevent senders from bypassing your mail flow rules by sending directly to recipients in your organization. It's great for reducing spam and ensuring all emails go through your proper filtering systems. Just be aware that legitimate bulk mail might get affected too, so monitor your quarantine after enabling this.Hope this helps!

Yeah, the previous answer is spot on about using PowerShell. I wanted to add that Microsoft actually recommends enabling this feature if you're dealing with a lot of spoofing attempts. Why you'd want this: Direct send allows senders to bypass some anti-spam checks, so enabling reject direct send means ALL emails must authenticate properly via SPF, DKIM, or DMARC. One thing to watch out for - if you have any legitimate applications that send using direct send (like multifunction printers or internal apps), they'll stop working and you'll need to reconfigure them to use proper SMTP auth. I found this great Microsoft documentation that explains the transport settings in more detail: https://docs.microsoft.com/en-us/exchange/antispam-and-antimalware/antispam-protection/configure-connection-filteringTook me about 10 minutes to implement and it definitely cut down on the phishing attempts we were seeing!