Service Restored at 2:04 p.m.: A technical issue with networking has been addressed. As a result, users should no longer be experiencing network and Internet slowness on campus.
Service Issue Reported at 11:05 a.m.: Some users are reporting slowness when accessing the network and the Internet. This issue may be related to other systems that are currently reported slowness, such as ISIS and Desire2Learn, OIT is investigating the situation, and more information will be posted here as it becomes available.
Incident Report Summary
On Monday, Nov. 5, 2012, at 10:30 a.m., OIT began receiving automatic notifications from our monitoring systems and clients concerning slowness for off-campus commodity Internet access. This did not affect all campus network users. The problem was caused by a denial-of-service (DoS) attack directed at a server at an affiliate from many places around the global Internet. Traffic from the DoS attack saturated the 1 Gbps connection in the same direction as our normal traffic. The most noticeable effect was very slow access to Desire2Learn. This should have had no effect on access to University Information Services (UIS) services, which we reach via our connection to the Front Range GigaPOP (FRGP).
Once it was determined the Level 3 connection was saturated, OIT redirected CU-Boulder network traffic away from the Level 3 link and routed the traffic via the FRGP. The problem was resolved on Monday Nov. 5, 2012, at 12:30 p.m. Because DoS attacks are unpredictable, OIT will continue to monitor the network for such occurrences. In addition, we are currently working to increase the bandwidth of the shared link to the commodity Internet.
Here is the full incident report (PDF).