DComTalk.com

Hello,

I am having a problem with "filtered packets" on the switches. I have a
2xMLT UTP between 470-48T and 450-24T. I upgraded the sw and tried another
ports, another cables, but situation is the same, a very big amount of
filtered packets at ports.

Does anybody know how to solve this problem?

Thanks,

Ivana

In article <d7kaqi$jaq$1@ss405.t-com.hr>,
Ivana Kvaka <vinan.xinxn@mt.ugarg.ue> wrote:
:I am having a problem with "filtered packets" on the switches. I have a
:2xMLT UTP between 470-48T and 450-24T. I upgraded the sw and tried another
:ports, another cables, but situation is the same, a very big amount of
:filtered packets at ports.

:Does anybody know how to solve this problem?

You haven't indicated what the problem -is-.

"filtered" packets are not necessarily an error.
For a bit of an explanation, please see:

http://64.233.187.104/search?q=cache:jc ... 00103.html
--
This signature intentionally left... Oh, darn!

Thanks,

Customer hasn't moved in the office yet, so there is nothing connected to
450. All I can see that 450 is transmitting multicast packets to 470. Why,
is it a normal behaviuor?

Ivana

Ivana Kvaka wrote:

Thanks,

Customer hasn't moved in the office yet, so there is nothing connected to
450. All I can see that 450 is transmitting multicast packets to 470. Why,
is it a normal behaviuor?

Ivana

Could you be more specific?

What type of multicast packets?

Have yopu looked to see what is going on with ethereal or some other
sniffer?

If you are doing IGMP, filtering multicast would be normal if no end
stations are there to receive.

-Sean

Ivana Kvaka <vinan.xinxn@mt.ugarg.ue> wrote:

Customer hasn't moved in the office yet, so there is nothing connected to
450. All I can see that 450 is transmitting multicast packets to 470. Why,
is it a normal behaviuor?

Make sure IGMP Snoop Proxy is turned off on the 450. Plain IGMP Snoop
is fine, it is the Proxy feature that had some issues in some software
versions of the 450 that would cause multicast packets to be reflected
off the 450 and back out over the same port the packets originally
came in on.

Thanks, but from where are these multicast packets? There is nothing like
that at the network, we don't use multicast. Is it possible that 450
generates itself multicast? Or some application?

Ivana

Ivana Kvaka wrote:

Thanks, but from where are these multicast packets? There is nothing like
that at the network, we don't use multicast. Is it possible that 450
generates itself multicast? Or some application?

Ivana

Well, obviously somewhere you ARE using multicast, you just don't
realize it. It may be unintentional -- perhaps you are doing something
that uses multicast but didn't realize it.

#1 candidate i'd say would be Spanning Tree. BPDU's go out via
multicast. If you have not diabled spanning tree on the switches, then
the switches themselves will be sending multicast packets.

#2 Router discovery - many devices will run this protocol by default
unless you specifically disable it - it uses multicast.

Since you have not told us what IS connected to the switches (ie: what
type of devices, what OS) it's a little hard to guess what the source of
the multicast packets is.

If it is really important that you know, download a copy of ethereal,
set up a mirroring port on one of the 450's and capture all the
multicast traffic. Look at the packets and see what is sending the traffic.