We all get those requests where there is a certain service that requires to send mails by using your company email server. Whilst an open relay is generally a way to get your domain blacklisted forever, allowing an internal relay is usually a necessity. By default Exchange is setup to deny relaying from any IP address, including your internal network. In this section I will show you how to allow relaying from your internal network. Exchange 2003: 1. Open the Exchange system manager 2. Expand the ......