[netflow-tools] variable delay for log

Damien Miller djm at mindrot.org
Fri Jun 15 09:13:10 EST 2007

On Wed, 6 Jun 2007, Õ½úѧ wrote:

>          I am new to use flowd-0.9 to receive NetFlow v9 from Cisco router.
> Everything seems to be working except that I noticed when the flowd process
> is activated; there is a variable delay when the log file receives data. The
> delay is less than half an hour but usually nearly half an hour.

The delay occurs because your router will only send flows when they expire
from its cache, which can be infrequent especially if your router is not 
busy. You can tweak this on your router by issuing commands like the 

ip flow-cache timeout active 5

This will cause your router to expire flows every five minutes.

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