Problems similar to those that began around 11:00pm, Fri 1/23, seem to have returned.
Info Systems brought a network administrator to campus at noon and began debugging the problem. At about 1:15pm it was determined that the problem is caused by a number of computers in the Residence Halls flooding the network with data that is recognized by the firewall to be “problem connections”. The firewall then started to deny these connections but the volume is too great for it to deal with, its memory filled up and inconsistent network behavior developed in many areas.
At 1:15pm the network administrators shutdown all network connectivity going into and out of the entire Residence Hall network segment. We will try to isolate the computers that are causing the problem to see if we can restore network connectivity for the rest of the Residence Hall connections. This may take several hours.
A number of odd characteristics have been observed on the network during the past week, beginning with the extreme slowdown last Monday evening (1/19) that lasted about 4 hours. Another observation that Info Systems made on Thursday and Friday was that a number of computers in the Residence Hall network segment were transmitting packets of unusual data that looked somewhat like a virus. One of these computers was brought into the HelpDesk area and examined by technicians to see if the virus could be identified. A scan of that system revealed no identifiable virus but an unusual fileset was found. However, tech support did submit a notification to Sophos, asking them to comment on the findings. As of 1:00pm today (1/24) no response has been received from Sophos.
As of 2:00pm (1/24) we believe that there are a number of computers on the Residence Hall LAN segment that have something on them that is sending lots of “bad data” to the network that is choking the firewall.
By 4:00pm the problem computers were identified and their connections to the network were disabled. Info Systems will work with these students on Mon, 1/26, to find a solution to clean their computers and re-enable their network connections.