Office 365 (Exchange Online) does not remove the user’s private IP address (x-originating-ip) from the header of sent emails. This causes a privacy risk that allows all recipients to easily see your home IP address by checking the email headers.
Fortunately it’s pretty easy to configure Office 365 to remove your client IP address from emails before sending them out.
The following instructions are for Office 365 Business subscriptions. Office 365 Home and Outlook.com already remove the private IP address automatically so you don’t have to do anything.
How to remove IP addresses from all emails sent by Outlook or other mail clients through Office 365/Exchange Online
- Go to the Exchange Admin Center (outlook.office.com/ecp)
- Click on mail flow
- Click on rules
- Create a new rule
- Copy the conditions and actions listed below:
I also recommend selecting the “Defer the message if rule processing doesn’t complete” to make sure that the rule removes the IP address from all outgoing emails.
This will hide your private IP address, the only email address attached to the email will be the public IP address of Office365/Exchange Online mail servers.