On Tue, 2003-08-19 at 16:12, Jack Bates wrote:
Number one use for netflow, scan detections. I detect most users infected with a virus before remote networks can auto-gen a report. I also detect mail being sent from various customer machines. High volume traffic flags me so I can investigate if it's spam or not.
Cool.. I never thought of using it for this...
I can tell you (well, I won't without a court order, but I could) the username, or customer name (if static), of every worm infected user on my network at any given point in time. 50+ inactive flows for an IP address is definite worm sign. If you want to be more specific, do sequential scan checks on the flow data. Has been very useful in dealing with Blaster.
Worm Sign... Dune... Cool :) We used ip accounting the other night to detect and disable a large number of worm infected users that took out the router completely.. I think net flow would have been too much overhead at the time... Once we were down to a more manageable number of infected users, we used netflow to pinpoint them immediately... (Note, we don't leave netflow on all the time)
Netflow is particularly useful when utilizing NAT, as it's much easier to collected netflow data than translation tables.
On a cold, boring day, you can setup aggregates and generate cute little statistics for all sorts of things, and I hear it's useful in some scenarios.
Sounds like fun... I wish I had slow boring days... *grin*
-Jack --
Jason H. Frisvold Backbone Engineering Supervisor Penteledata Engineering friz@corp.ptd.net RedHat Engineer - RHCE # 807302349405893 Cisco Certified - CCNA # CSCO10151622 MySQL Core Certified - ID# 205982910 --------------------------- "Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world." -- Albert Einstein [1879-1955]