Do you have a lot of switches in the network?
The problem I've seen is you will see all the other
non broadcast traffic on the switch you are connected
to (with the port set to replicate traffic), but will
only see broadcasts from all the other switches in the
network. This can make it look like an ARP storm. The
fact that it is 78 percent ARP traffic may simply be
because there isn't much Unicast traffic on the switch
you are monitoring compared to the broadcasts you are
getting from the entire company.
The real question is what is the Packet per second
rate of the ARP traffic and are they ARPs for known
hosts or simply something looking for unknown hosts to
respond.
Wes
--- eperez@xxxxxxxxxxx wrote:
> Well, the network is a 139.60.0.0/255.255.0.0 doing
> natting to the outside via
> PIX that NATs to 64.116.x.x. The network has around
> 200 machines.
> Yes, I know the 139.x.x.x is wrong but somehow they
> decided that was a good
> network (why do they want 65536 hosts in unknown to
> me..) But since they are
> doing NATting I see no problem related to this ARP
> storm. The net numbering can
> be fixed later.....
>
> A few minutes ago we also discover IPX traffic.
> About 10%. So they have a case
> of Lame sysadmins that do click-click-clik Windows
> installations.
>
> It has several jetdirect devices that are know to do
> broadcasts (will be checked
> and disabled if needed) but the devices are like a
> year old and the problem
> just started a few days ago.
>
> As per the validity of the ARP SRC and DST, I will
> check that tomorrow and do a
> repost to this list.The ARP list is so hughe and it
> was already closing time
> down here (gmt -5) that we were not able to verify
> it onsite.
>
> It cannot be nachy/welchia worm because thats for
> Win2k/XP and they have a lot
> of 95/98/NT machines. Only a few (less than 20) are
> XP Pro. Unless of course
> somehow they got a way to infect those older OSs.
>
> David: port mirroring is working fine.
> Peter: Ill check SRC and DST tomorrow and do a
> repost.
> Andrew: Well, Ill ditch MS technologies from my
> entire country if i could but i
> cant in this case. LONG LIVE *nix
> Brett: We also use static IPs. I will check for
> viruses using my personal laptop
> since I dont trust any of the customer's computer.
>
> Thanks to all, I will repost tomorrow.
>
> Erick.
>
> Quoting eperez@xxxxxxxxxxx:
>
> > My network started to slow down a few days ago. So
> I installed latest
> > ethereal
> > and winpcap for windows in a NT Server 4.0. All
> the network is switched and
> > I
> > was trying to find some cause of slowdown. I am
> aware of the limitations of
> > sniffing on a switched network so I set the
> switches to replicate traffic so
> > i
> > can see it with ethereal.
> > So far so good, but in the main ethereal windows
> where it shows how many
> > packets
> > per protocol has received during the sniffing
> session I found that after 1
> > hour
> > of sniffing 78% of my traffic was ARP and the rest
> was TCP(normal smb, tns,
> > etc).
> >
> > All the network has windows machines
> (95,98,NT,2000,XP) all servers are NT
> > 4.0
> > and the network has one PDC one BDC and one WINS
> server.
> >
> > I did a search on the mailing list but found no
> clue about it. Maybe this is
> > normal but I just dont know.
> >
> > Comments/Flames/Suggestions are welcomed.
> >
> > Erick.
> >
> >
> > _______________________________________________
> > Ethereal-users mailing list
> > Ethereal-users@xxxxxxxxxxxx
> >
>
http://www.ethereal.com/mailman/listinfo/ethereal-users
> >
>
>
>
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>
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