Guidelines and Registration Form for Use of the ITS Mail Relay Service


ITS offers a mail relay service that will relay mail on behalf of other machines, devices, and applications that are unable to use authenticated SMTP for sending mail. This document outlines the guidelines for using that service and provides a form that departments can fill out to register their IP addresses to use the service.

Note The registration form is available online.

About the Mail Relay Service

ITS offers a mail relay service which relays mail on behalf of other machines, devices, and applications that require an "outbound mail server" and are unable to use authenticated SMTP—that is, that are unable to use

The mail relay service is not intended for use by personal workstations or applications that support authenticated SMTP. It is also not intended for relaying unofficial, unsolicited bulk mail.

To prevent unauthorized mail from being relayed, the service will only accept mail from a list of approved, U-M IP addresses. Departments must register their U-M IP address(es) with the service in order to use it. Use must comply with Information Technology Policies at the University of Michigan.

The University of Michigan Postmaster Team manages the mail relay service and reserves the right to block access without notice from any IP number that disrupts mail delivery or violates U-M IT policies and guidelines.

Registration Form for the Mail Relay Service

If your U-M department would like to register to use ITS's mail relay service, please complete this online form.

When you have completed the form, click the Send Form button at the bottom of the page.

After You Have Submitted the Form

  1. The Postmaster team will review the form. You may be contacted for additional information should the need arise. IP addresses are registered individually. A confirmation message (one for each IP registered) will be sent to the "Contact e-mail address" listed on the form.

  2. After you receive the confirmation message(s), configure your newly registered machines to use the mail relay service for sending mail. The machine name for the mail relay service is You can direct unencrypted mail to port 25 and encrypted mail (STARTTLS) to port 587.

Last Updated: 
Thursday, March 20, 2014