Security Basics mailing list archives
RE: weird
From: jeff.frost () us army mil
Date: Tue, 24 Feb 2004 13:03:46 +0100
Kenzo, I have seen instances similar to this when a physical loop is created on the network. However, since this is normally done on accident it can take some time to find the problem and resolve it (it will not resolve itself). Since this problem seems intermittent, it is more likely that you are seeing a broadcast storm from a malfunctioning nic, etc... It is also unlikely that you will get the information to track down the problem from ntop. You need a network monitoring tool to capture this data. Hope this helps... -----Original Message----- From: kenzo [mailto:kenzo_chin () hotmail com] Sent: Friday, February 20, 2004 3:15 AM To: security-basics () securityfocus com Subject: weird This weird thing happened at work. Everything was fine, then all of sudden the whole network freezes. All the swicthes and hub lights are blinking like there's no tomorow. So much traffic going on I can't even ping the computer accross me on the same switch. Then it stops and everything is back to normal. That happened twice. I use Ntop to watch for protocol usage to find infected computers(when that happens) and people using other protocols that the're not suppose to. When this happens the box crashes. I tried using ethereal to see if I saw anything but of course it doesn't happen when I'm ready for it. I looked thru the traffic that I gathered from ethereal but none seem to really stick out. I'm not an expert, so the only thing that I know that will do the same thing is flooding the network with ramdom MAC addresses. Or maybe a major arp flooding or something. I haven't tried the arp flooding, but I know that the Mac flooding does the same thing. What could it be? Did someone flood the network on purpose? If so, how do I track it? Or could it be that a bad Nic or device on the network just went crazy for a while. (That's what my boss seems to think.) Even then, how do I track it? Thanks. --------------------------------------------------------------------------- Free trial: Astaro Security Linux -- firewall with Spam/Virus Protection Protect your network with the comprehensive security solution that integrates six applications for ease of use and lower TCO. Firewall - Virus protection - Spam protection - URL blocking - VPN - Wireless security. Download 30-day evaluation at: http://www.securityfocus.com/sponsor/Astaro_security-basics_040219 ---------------------------------------------------------------------------- --------------------------------------------------------------------------- Free trial: Astaro Security Linux -- firewall with Spam/Virus Protection Protect your network with the comprehensive security solution that integrates six applications for ease of use and lower TCO. Firewall - Virus protection - Spam protection - URL blocking - VPN - Wireless security. Download 30-day evaluation at: http://www.securityfocus.com/sponsor/Astaro_security-basics_040219 ----------------------------------------------------------------------------