Re: port flapping

"sharqi" <sharqi@xxxxx> wrote:

>I 've got a problem with Catalyst 2980G. Ports on it have been flapping.
>This problem concern only one switch in my network only one vlan. There are
>no errors on this ports, it seems like broadcast or unicast is flooding but
>I don't know how to fix it.
>


WHat kind of flapping? If the port is going down and up then I would
chaeck that PC for virus/spyware. Each time we have a port doing this
it is because of an infected PC that is scanning every IP in existence
as fast as it can.

If it is MAC address flapping between two ports, you may have a
multi-nic server that needs etherchannel support from the switch.

If macs are flappiing between cross-over/trunks you may have some kind
of loop or repeated fail-over.
DiGiTAL_ViNYL (no email)
.

Relevant Pages

  • Re: Require clarification on IEEE 802.1D -2004 spec on Conformance
    ... Extreme and found out that from all the Ports, the BPDU has encoded ... the Same MAC address.this Encoded MAC address is the same as Source MAC ... >> MAC address for each of the Ports on my switch? ...
    (comp.dcom.lans.ethernet)
  • Re: Antisniffer measures (digest of posts)
    ... traffic off the other users ethernet ports; ... > switches with hardcorded MAC addreses for each port. ... switch that allows you to control the behavior of the network. ... Put each host on a reparate NIC. ...
    (FreeBSD-Security)
  • RE: Wireless blocking
    ... should be able to track down where the AP plugs into the switch. ... You can also look for ports that have ... multiple mac addresses on them since on the edge your switches should ... Wireless AP through wire. ...
    (Security-Basics)
  • RE: how to flood the mac address table of a switch?
    ... Connect a cross-over cable between two switch ports. ... Remember to re-enable spanning tree as soon as you're ... The result, though, is that every MAC address on your network ...
    (Security-Basics)
  • Re: What is the difference between up and down link on LAN switch?
    ... Not for your average consumer-grade switch. ... They have a cache that keeps track of which MAC addresses are ... sending packets in which ports. ...
    (comp.arch.embedded)