NIU's Email Block List - NIU - Division of Information Technology




NIU's Email Block List

Some email messages to NIU Outlook accounts are blocked at the enterprise level regardless of settings users have made in CanIt. 

When a message contains one of the following blocked components, a delivery failure message is returned to the sender's email server. Depending upon that server's configuration, this error message may or may not be passed along to the actual sender. This means that the sender of such messages may not be notified that the message was blocked. Since this is a setting at the sender's server level, ITS has no control regarding if these error messages are received by the sender.

Messages with an excessive spam score

Messages that receive an excessive CanIt spam score (of over 20) will be blocked. This is regardless of any individual CanIt settings made by the intended recipient (even if the intended recipient has opted out of spam scanning altogether).


Since many worms and viruses propagate through the use of e-mail attachments, some attachments are blocked at an enterprise level.

To receive an email with with a blocked type of attachment, have the sender rename the attachment. For example, rename "patch.exe" to "patch.zzz." As always, never open attachments that you are not expecting.

Messages with attachments of the following types are blocked:

  • .bat
  • .cab
  • .cmd
  • .com
  • .cpl
  • .exe
  • .hta
  • .pif
  • .scr
  • .vbs
  • .zip

Other Blocks

Domains, hosts and addresses in reputational advisory services, including but not limited to, may also be blocked. Mailers who have sent phishing or spam messages to NIU may also be blocked. Questions regarding blocks should be forwarded to