Static IP restriction question

[David_Dunlap]

I'm looking for a way to prevent a device from being connected to my network with a static IP address that is the same as other devices that I've already assigned static IP addresses to. For example, I don't want a random user to be able to set their laptop to a static IP of 192.168.1.1 and cause a conflict with a server that has the same IP address. I would like to be able to, at a switching level, disable network access to that user's pc and avoid the conflict. I would like an automated way to do this, if possible. Does anyone know of any solution? Thanks!

[pstebner1]

Hi David-

I'm not sure what kind of switch you are using, but I assume that it supports 802.1x, which is a Layer 2 based authentication method. This is exactly what you need in your situation, as it will keep any unauthorized pcs off of your network.

Here is a tech note on how to configure it, specifically for a 3750 switch:

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.1_19_ea1/configuration/guide/sw8021x.html

hth,

Paul