Configure SPF for Xink Server-Side Email Routing

Short answer:
If emails processed by Xink server-side are flagged as spam, update your SPF record to include include:spfrerouting.xink.io or add the relevant Xink relay IP address for your region.

Why SPF matters

SPF (Sender Policy Framework) is used by Microsoft 365 and other mail systems to verify which servers are allowed to send emails on behalf of your domain.

When using Microsoft 365, your domain typically already includes:

include:spf.protection.outlook.com

This allows Microsoft 365 to send emails on your behalf.

When using Xink server-side, emails are processed by the Xink ReRouter and then returned to Microsoft 365 for delivery. To prevent spam filtering issues, Xink must also be authorized in your SPF record.

Recommended configuration

Add the following include statement to your SPF record:

include:spfrerouting.xink.io

Example SPF record:

v=spf1 mx include:spf.protection.outlook.com include:spfrerouting.xink.io ~all

Alternative: Use IP addresses

The spfrerouting.xink.io include uses a soft fail (~all). If your policy requires stricter control, you can instead allow Xink by adding the specific relay IP address for your data center.

Xink relay IP addresses

Example (US data center):

v=spf1 mx include:spf.protection.outlook.com ip4:52.186.121.110 -all

Result

Emails processed by Xink will be recognized as trusted senders, reducing the risk of spam filtering or delivery issues.