North American Network Operators Group|
Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical
Re: Gb ethernet interface keeping dropping packet in ingress
Joe Johnson wrote:
Now, we do try to monitor some things like that. We have several cronsOur list of crons is growing too...
We do the Nachi/Blaster 445 and ICMP pings with a route policy map on our core so as not to disturb the PIX with senseless traffic. We do at least catch the random Nachi probles (which are local), didn't work so sell with machines destined off the local subnet.One that helped out a lot recently was Nachi/Welchia search. Caught 40% of our subscribers that were infected, and helped stop all but 3 specific broadcast storms on our network. All the cron did was look for the specific ICMP packet that the virus put out, and flagged the connection in a list that is emailed to the NOC s
We do extensive ingress/egress filtering at the border that catches most junk from getting in our out. We're in the process of intergrating this into our Perfigo system, but we've only had the Perfigo solution in place for a few months. It has helped by logically micro-managing each station on their own logical /30 subnet that makes them up, but virii/worms that don't care about gateways and so forth aren't really stopped if they catch a 0-day, very few viruses make meaningful IP address guessing (they'll nail thhe local ranges first, but some go off-campus). This is hopefully caught by a script under developent that uses ipaudit (sourceforge.net) and keeps the top 10 traffic sources inbound/outbound, and cumulative counts each 30 minutes for how many local/hosts appear to be scanning, and likewise for the reverse.
We used to shut these ports down, but now we're having Perfigo lock them into a "quarantine" LAN where their situation is explained, and has hooks to our SUS and antivirus tools (AdAware, Spybot) with contact numbers for the helpdesk if they need assistannce.
So far, so good, but could be better.