On July 7, starting at approximately 10:30 a.m, UNL, UNK and UNO began to experience connectivity issues to Office 365. Outlook and other mail clients ceased connection and webmail was the only functioning access point for University users. An hour earlier, Microsoft reported an issue preventing Exchange Online users from sending mail.
After investigation by Microsoft and analysis by ITS Systems and Information Security teams, it was discovered that UNL's connectivity issue to email was confined to service over University of Nebraska networks. A new security filter was applied the same morning to UNL's intrusion prevention system to block a number of IP addresses that were scanning the University network anonymously. Included in the newly blocked IP hosts were selected Microsoft IP addresses which impacted service. Upon discovery, the designated IP addresses were removed from the filter and access to email service was restored at approximately 3:45 p.m.
ITS has made many enhancements in improving information security on campus. UNL intrusion prevention tools prevent, on average, 1 million to 5 million malicious attacks each day from reaching our network. The number and range of Microsoft IP service hosts change dynamically based on to the individual service provided, availability, expansion and scalability. UNL is currently examining the methods in which those changes are communicated to ensure this kind of incident is not repeated.
UNL Information Technology Services regrets this interruption of email service and apologizes for the inconvenience to the campus.
For additional questions, contact the UNL Computer Help Center at 472-3970 or Toll Free (866) 472-3970 or email at mysupport@unl.edu.