On Mon, 01 Jan 2007, in the Usenet newsgroup comp.os.linux.networking, in
article , Jim wrote:

>Sorry, this msg should be send to pl.comp.os.linux.

I can't read/understand Polish, but three things jump out at me:

>> Do tej pory miałem w switchu 3com 4250T około 35 kompów w LAN.
>> Switch

3Com 4250T switch

>> Tcpdump pokazał takie coś:
>> 10:52:28.671348 00:00:00:00:00:00 > 01:80:c2:00:00:01, ethertype Unknown
>> (0x8808), length 60:

[compton ~]$ etherwhois 01:80:c2
Non-existent address as of Dec 18 17:25:59 MST 2006 OUI file
0180C2000000 Spanning Tree (BPDU) (see keywords Spanning Tree)
[compton ~]$ zgrep 880[0-f] rfcs/ethernet-numbers.gz
[compton ~]$

Spanning Tree http://www.cisco.com/univercd/cc/td/...duct/rtrmgmt/\
"Understanding Spanning-Tree Protocol: Spanning-Tree Protocol is a link
management protocol that provides path redundancy while preventing
undesirable loops in the network. For an Ethernet network to function
properly, only one active path can exist between two stations..."

Perhaps that may be related? You may want to wander over to the Usenet
newsgroup comp.protocols.tcp-ip, and perhaps comp.dcom.lans.ethernet.

Old guy