Relevant Products: Mail Disclaimers | Signature Manager Exchange Edition
Scenario
Users are receiving spam emails from senders that have been spoofed. The message is made to look even more authentic when Mail Disclaimers appends the sender’s signature to the message.
Cause
The problem occurs because the email domain specified as the sender on the email received has been spoofed. Mail Disclaimers has appended a signature to the spoofed email because the sender and/or recipient on the message matches conditions specified for the relevant signature policy.
Exclaimer processes any messages submitted to the server where it is installed - this includes emails sent internally, externally, as well as inbound.
Resolution
Mail Disclaimers cannot identify emails from senders that have been spoofed - nor is it possible to turn off the direction of mail flow that Exclaimer processes.
Using an SPF record will ensure that your domain is not spoofed, as only senders from authorized IP addresses will be permitted to send email from the domain.
If you do not know how to create or update your SPF record, we recommend that you contact your hosting service provider, or whoever is responsible for hosting within your organization.