Solved

Bad Switch Mac Address

Posted on 2013-11-19
4
364 Views
Last Modified: 2013-12-09
Hello,
I am currently having a problem in my network where there is a device that I’m not aware of that is trying to become the Root Switch, the Mac address of this device is  showing up as an manufacture I’m not using, Is there a good way to track down were the device could be located?

Thanks
0
Comment
Question by:ahmad1467
  • 2
4 Comments
 

Expert Comment

by:Dhurken
ID: 39660040
What model switches are you using?
0
 
LVL 12

Expert Comment

by:Infamus
ID: 39660150
If it is Cisco switch, you can run one of the following command depends on the version of IOS.

sh mac address-table address xxxx.xxxx.xxxx

sh mac-address-table address xxxx.xxxx.xxxx

This will tell you which switch port the MAC address is connected to.
0
 

Expert Comment

by:Dhurken
ID: 39660180
As a follow up to Infamus, if you have a larger infrastructure, you may end up hopping from switch to switch to track down the actual switchport where the device is connected.

If so, you can use sh cdp neighbors detail to see the other Cisco devices connected to your current switch.
0
 
LVL 17

Accepted Solution

by:
TimotiSt earned 500 total points
ID: 39660334
If it does become the root switch, the STP 'root port' will point towards it.
As @Infamus says, you might find it in the mac table with 'sh mac address-table'.
But the main point would be to implement BPDU protection on the edge ports. BPDU-guard can shut down the port, in which case you can find the user without network access pretty quick (if that's accceptable in the organization)...
0

Featured Post

Free Tool: Postgres Monitoring System

A PHP and Perl based system to collect and display usage statistics from PostgreSQL databases.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

 One of the main issues with network wires is that you never have enough.  You run plenty and plan for the worst case but you still end up needing more.  What many people do not realize is with 10BaseT and 100BaseT (but not 1000BaseT) networks you …
Hi there, This article summarizes what you need if you are going to set up your home or small business Network Attached Storage (NAS) to be accessible from the internet. Of course there are configuration differences based on your NAS or router ma…
Here's a very brief overview of the methods PRTG Network Monitor (https://www.paessler.com/prtg) offers for monitoring bandwidth, to help you decide which methods you´d like to investigate in more detail.  The methods are covered in more detail in o…
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…

713 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question