Help fixing duplicate IP address on Vlan1

[Clay Plaga]

I am getting an error on my Cisco 2960G switch that says “ duplicate address 192.168.1.10 on Vlan1, sourced by 08cc.68bc.1304.” The switch is connected to a Cisco 1800 router. This is a test network that I am using to study for my Cisco certification.

I am just beginning to learn switches.

I have included 2 screenshots from the switch. 

Can someone assist me with fixing this error. What should I check first?

I

[chrihussey]

Identify the ports that the mac addresses belong. "show mac address-table xxxx.xxxx.xxxx"

Once you find the ports, identify the attached devices and check their IPs.

Also, not sure how involved of a test network you have but if you can post the configs of the 2960G and 1800, it may be easier to help.

Regards

[Clay Plaga]

Thank you for helping me. What do I enter for the x's?

[chrihussey]

The MAC address

"show mac address-table address 08cc.68bc.1af0"

[Clay Plaga]

I really appreciate you trying to help me, but the show mac address-table is not working for me. I have a cisco 2960g switch. I have included a screenshot. Thank you.

[chrihussey]

There is no hyphen between mac-address:

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

If you type:

sh mac ?

it gives you the next options to help you step through the command.

[chrihussey]

I have a 2960, this is the syntax as posted earlier:

show mac address-table address 08cc.68bc.1af0

You'll need to do this command for both MACs that are showing up as a duplicate to locate both devices.

[Clay Plaga · Accepted solution]

Thank you for your help. Yes, I did fix it. With the commands you gave me, I found the MAC address, and then I traced the MAC to one of my access points. The access point had the wrong IP address. I checked my DHCP on the domain controller, and found that IP address had been issued a lease. I deleted the entry and it cleared the vlan error. Thanks again!