Interesting netflow entry

Bill Nash billn at odyssey.billn.net
Mon Feb 6 23:19:59 UTC 2006


On Mon, 6 Feb 2006, Wil Schultz wrote:

>
> Here is another pattern, sourced off of one the destinations:
>

[snip]

You may find it far simpler to just ask the person who owns the sources 
that those packets are. While this may not be politically feasible (insert 
network and privacy policies here), given the amount of VPN traffic that's 
encapsulated in UDP, that may be anything. The problem with netflow is 
that it does reveal many interesting, hypnotic patterns inside your 
network. Having spent my share of time on the receiving end of that 
lunacy, I can only offer this advice: Drinking from the firehose is only 
funny for a little while.

Depending on your deployment method (transit flow monitoring vs locally 
sourced, data center vs office campus, college campus vs four hippies with 
tin cans), identifying flows may be far easier if you have a network 
inventory to refer to. Even something as simple as parsing XML output from 
NMAP into a db will give you better insight into what your flows are.

Incidentally (because I ask everyone this), what's your flow volume 
(flows per second)?

- billn



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