If you receive email about a suspect attachment or an undeliverable message

To protect computers at Indiana University, UITS has enabled filters for attachments that have been known to carry viruses; see Types of attachments blocked from IU email accounts. If you receive a message from "Mail Delivery System <MAILER-DAEMON@indiana.edu>", you may have attempted to send one of the prohibited attachment types. This can happen whether you are sending to or from an IU email account; as long as the message passes through the IU mail relays, it will be blocked. (Alternatively, someone may have spoofed your email address; see If you get undeliverable or bounce messages for email you didn't send)

Because email systems can vary in how they handle these messages, you may not receive an explanation in the message itself. Look for one or more of the following:

• A subject line of "Delivery Status Notification (Failure)".
• "Undeliverable:" or "[Suspect attachment]" in the subject line. Note that this may not be present in the subject line as you receive it, but may be in the original subject line, now in the body of the message.
• A message body that reads:

  The following message to <username@indiana.edu> was undeliverable.

  The reason for the problem:

  5.x.0 - Message bounced by administrator

• A message body that reads:

  Suspect attachment [filename] was removed. See http://kb.iu.edu/d/bdaw for more information.

Any of these can indicate that your message did not reach the recipient.