Check the back traffic - this has come up before - IIRC there are two kinds
of sFlow packets, one is some sort of summary which ntop sees and ignores.
So you may not really be getting data. But I'm fuzzy on the details -
google for it. Or check the FAQ and see if this makes sense:
Q. sFlow doesn't work.
A. Check this out:
This talks about a bad experience I had setting up sFlow reception. For
the longest
time, I could see that ntop was getting sflow packets, but no data
would show up.
It turns out the switch I was exporting from didn't see any real
traffic, and it was
just sending COUNTERSAMPLE packets.....
- - - - - - - - I figured out that it was indeed "invalid" sflow
packets.
Apparently, sflow sends COUNTERSAMPLE and FLOWSAMPLE packets.
COUNTERSAMPLE packets
give a quick look at interface counters on the machine, whereas
FLOWSAMPLE packets
are actual packet fragments from IP connections. Ntop seems to simply
parse,
debug_print, and discard COUNTERSAMPLE packets...which made it
confusing to look at
the debug output and say "wow, lots of sflow coming in!" when in fact
it was just for
show, as Burton suggested. I added more switches (with active
connections) to the
switches sending sflow packets and I now have hosts with pretty graphs.
-----Burton
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of
[EMAIL PROTECTED]
Sent: Tuesday, March 29, 2005 8:14 AM
To: [email protected]
Subject: [Ntop] sFlow not working!
Hello,
I'm trying to activate sFlow with Ntop 3.1 and it's not working, no trafic
visible. Here my config:
sFlow version: 2.99
Local Collector UDP Port: 6343
Virtual sFlow Interface network Address: 172.16.0.0/255.255.0.0
Flow Senders IP is: 172.16.2.251
Flow Collector (Ntop) IP is: 172.16.1.215
Thanks,
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