As i know NO . becouse i have :

1) it is the main server wich run as an DHCP wit clearos ip it is 192.168.0.254

from it it is conected an switch and from switched are conected pc's and 3 acces points .

All the acces points as i know have DHCP disabled . And thats the problem other people who come next to the place and they try to connect to the network many of them use phones . There as a problem wit a person who entered wit an samsung old phone on wireless conected to our acces point internet and on the clearos he was show he used ip 192.168.0.22 but if i scan entire network wit other software i see that she does not have the ip 192.168.0.22 and the 192168.0.101.

Thats the problem. I do not know what it happends and how .

If i search she's samsung phone i see ip it is 192.168.0.22 but in fact the ip it is 192168.0.101 . Really strange .



SCHEMA :

CLEAROS - > SWITCH -> Acces Point - > Phone Samsung .

Could there ba another DHCP server anywhere in your network?

There are acces points not rooters .

I did buy acces points .

Are you using routers as access points? If you are, have you remembered to disable all their DHCP servers?

If you want to find multiple devices sing the same MAC address, try using the "arping" command. There are examples on this forum.

You may find your user has given himself what is supposed to be a fixed IP address on his home network, but he is carrying over the address onto your network. This is a good reason not to use 192.168.0.0/24 and 192.168.1.0/24 as LAN subnets in ClearOS. They are too common on domestic routers.

I don't know if you can block the person with a couple of iptables rules. You can stop him accessing the internet, but it may not stop internal switches talking to him:

iptables -I FORWARD -m mac --mac-source aa-bb-cc-dd-ee-ff-gg -j DROP

iptables -I INPUT -m mac --mac-source aa-bb-cc-dd-ee-ff-gg -j DROP