topic Hi,What switches are you in Network Security

Preventing IP duplication while useing DHCP sever.

davidsonyo — Fri, 21 Feb 2020 13:32:34 GMT

Hello lads,

I was wondering the other day how could I prevent a host causing IP duplication on the network.

The situation:

We are using DHCP sever on the network with MAC based authentication, so only users get address from the DHCP who's are on the list with their MAC address.

But people who give statically IP address to their device can use the network. If they can find out

So here comes the problem. In some case they add IP address which is already used and it will cause IP duplication.

I want to prevent this to happen by shutting down the port or prevent this to happen.

Mean while I also want to manage it dynamically by not to add each MAC address of the servers or the gateways etc.

Any help is appreciated!

Thanks,

Dave.

Hi,What switches are you

johnd2310 — Mon, 10 Aug 2015 02:26:35 GMT

Hi,

What switches are you using? You could look at dhcp snooping, arp inspection and source guard. This will force users to use dhcp.

Thanks

John

Hello, We are using 2950,

davidsonyo — Mon, 10 Aug 2015 08:42:00 GMT

Hello,

We are using 2950, SG200, 3560 switches.

Do you have best any best practice list how to implement those with functions ?

Thanks!

Dave.

Hi, Have a look at the

johnd2310 — Tue, 11 Aug 2015 00:11:33 GMT

Hi,

Have a look at the following docs:

http://www.cisco.com/c/en/us/support/docs/switches/catalyst-3750-series-switches/72846-layer2-secftrs-catl3fixed.html

http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Security/SAFE_RG/SAFE_rg/chap8.html#wp1053552

Thanks

John