Network monitoring

Murray Taylor murraytaylor at bytecraftsystems.com
Wed Nov 24 14:46:14 PST 2004


On Thu, 2004-11-25 at 08:27, Haulmark, Chris wrote:
> Someone broke the silence: 
> 
> > I apologize that this probably isn't the most relevant
> > list to ask this on. Suggestions for better lists will be welcome.
> > 
> > I'm trying to monitor traffice on a 100BaseT ethernet
> > network link. I split the line, put a "hub" in and am
> > trying to run tcpdump on a box off the side of the
> > hub.
> > 
> > Unfortunately, it turns out the hub isn't a hub, it's
> > a "switching hub" (what's not a switch about this? I
> > don't get it). Consequently, all I see are arp
> > packets, bootp packets, and the odd broadcast. I went
> > to a local store to buy a hub, and guess what, they
> > sold me another switching hub, so that has to be
> > returned :(
> > 
> > So, the question is, can anyone tell me the
> > manufacturer and product name of a real (dumb) hub? I
> > could use 10baseT instead if necessary, I just need
> > something cheap that is a simple repeater. Of course,
> > nobody advertizes "our hub really is a totally dumb
> > hub, not like those fancy switching hubs the
> > competition sells" ;>
> > 
> > Any suggestions?
> > 
> 
> I ran into the similar problem.  I just looked elsewhere for a cheap hub. Ebay was the favorite place for me.  For you, just swing by a Pop/Mom/Family kind of computer stores.  They might sell few old hubs that doesn't have switching capabilities at a low price.
> 
> Chris Haulmark
> 
> > Thanks
> > Simon
> > 
> > 
Would this work for you

1 - install a second NIC in the BSD box
2 - configure it as a bridge with no IP numbers on the NICs
     (Ahm jist sittin' 'ere, passin' stuff thru!)
3 - tcpdump -i fxp0      or      tcpdump -i fxp1 
     as appropriate

A NIC is easier to get than a dumb hub these days ...


-- 
Murray Taylor
Special Projects Engineer
---------------------------------
Bytecraft Systems & Entertainment
P: +61 3 8710 2555
F: +61 3 8710 2599
D: +61 3 9238 4275
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E: murraytaylor at bytecraftsystems.com
or visit us on the web
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http://www.bytecraftentertainment.com



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