Information Technology Services is still searching for the source of a firewall problem that brought Yale’s network to an intermittent standstill Monday.
The disruption severely slowed traffic to all the University’s servers, including the ones for its Web sites and e-mail, for roughly an hour at 4 p.m. and again at 9 p.m. Officials said they have now determined that the trouble stemmed from an information overload in Yale’s protective firewall, but a continuing analysis of the data has yet to show what information might have caused the overload.
Though attacks on the firewall are common and are not perceived as a serious security threat, Monday’s disturbance was troublesome because it all but shut down the network, officials said.
“We’ve never had it so busy that it basically shut down,” Information Security Officer Morrow Long said. “We’re going back through all the diagnostics, looking to see if there’s some type of sign.”
ITS administrators said the problem could have been the result of a software malfunction, an outside attack, or both, though external causes seem more likely. The list of potential culprits ranges from attacks at the lowest levels of programming to large-scale assaults over Web sites or e-mail, they said. Typically, firewalls offer protection against known Internet threats.
“The firewall device slowed down — it was busy with something — to the extent that traffic was going through it at a very slow rate,” Director of Network Services Joe Paolillo said. “They’re a good set of protection, but nothing’s foolproof.”
Technicians restored the firewall to normal by rebooting the system, perhaps implying that the problem originated in sources already targeted by Yale’s protective settings, Long said. Rebooting automatically disables temporary firewalls, which Yale recently implemented to protect against several malicious Eastern European Web sites.
Long said he does not believe the loss of the temporary firewalls poses a larger threat to Yale’s systems. The servers themselves have layers of protection against attacks, though having to fend off them off without the aid of a general firewall can slow system performance. Still, the reboot appears to have had no side effects, officials said.
Adam Metzger ’08, who was trying to download notes for a midterm when the network failed, said he was particularly annoyed by the problem because he did not know what caused it and student computing assistants were unable to help.
“The biggest inconvenience is that I think it’s a problem with my computer, and I go running to the CAs because I don’t know how long it’s going to last,” he said.
The slowdown came a week after ITS upgraded Yale’s e-mail servers to relieve an overload that had degraded performance since the beginning of the year. Based on the reduced number of complaints to the Help Desk, Service Manager John Guidone said, the upgrade appears to have solved that problem.
Officials announced Wednesday that much of the network will be down intermittently over the weekend for other scheduled upgrades. The statement was e-mailed to the Yale community through a new ITS Communications Department, established in November, that helps to manage ITS Web sites and craft announcements for its other divisions.
Jane Livingston, associate director of Support Services, said the three-person department aims to keep students up to date on the general status of ITS.
“It’s really exciting to have a communication department within ITS, and hopefully we can do a lot more than we’ve done in the past,” she said. “We want to get out meaningful information in a timely way.”
Paolillo said the firewall failure may remain a mystery if ITS is unable to determine the source within a few days.