Why am I not receiving email from people outside IU?

Sometimes email sent to you from outside the Indiana University email system (i.e., by someone using a different Internet service provider) is not delivered because of bandwidth limits that UITS enforces in its efforts to battle spam.

One of the ways IU protects its email system from huge volumes of spam is by limiting each host to sending only several hundred messages per minute. If someone is trying to send email to you from a non-IU host that has exceeded its message limit, that email will probably not get through to you. Furthermore, the sender may not receive any notification that the message was not delivered. This is because the sending (i.e., non-IU) host is not fulfilling its responsibility to communicate to the sender any failed or deferred connections.

With any message sent from outside the IU email environment, multiple points of failure are possible. In many cases, the failure occurs before the email reaches the IU network. In other instances, a message may reach the IU network but be refused because of the connection limits described above, or deferred because IU's email system resources are at capacity for the moment. Regardless, the sending server is still responsible for reporting a delivery failure or delay to the sender.

Also, to limit the effect spam has on the university's academic mission, IU email system architecture separates its internal university mail flow from the rest of the Internet. This provides a layer of protection that allows IU email to flow reliably between its students, faculty, and staff members. For this reason, it is expected that all official university email be sent via the IU system, and not through external, non-IU hosts. For more, see At IU, what is the policy about official communications from the university to students? For further information about how IU is fighting spam, see What does IU do to protect users from spam and virus-infected email?

The information discussed above describes only a few reasons that you may not be receiving some of your email. For information about other possibilities, see At IU, why am I not receiving all of my email?

This is document aqdk in the Knowledge Base.
Last modified on 2017-05-16 12:13:30.

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