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IP address or subnet already exists

Occasional Advisor

IP address or subnet already exists

When configuring a new VLAN on my 2910-48, I receive the message "IP Address (or subnet) already exists". I've pinged the IP and received no return. This 48-port switch replaced a 24-port switch. I cannot find a reference to this IP address in any of my documentation.


How do I remove this IP address so I can reuse it? Does the "/24" at the end of the IP address refer to something on the old switch?



Occasional Advisor

Re: IP address or subnet already exists

Hi Frank


In order for us to help you, please post the entire configuration file of the switch.

You have to login via console to the switch, acces the CLI (if the menu appears, use option 5) and issue the following command:


Switch# show config


As for the /24 part of the ip address it represents the netmask. /24 stands for / 24 is the same thing as /


24 bits are used to create the netmask and you get a type C IP address.


More info here:

And a great tool here: