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zyklon
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How to recognize and block if used a fixed ip address??

Fri May 20, 2016 9:05 am

Hi guys.
I want to know if possible how to recognize and block a used ip address on the network by mechanism or protocol. For example, if an user connects her PC and he set an fixed ip on the NIC of this pc, and if this fixed ip is used through the network, the protocol or mechamism detects this fixed ip and block (by shutdown on the port o something else) the data packets sends by the NIC of the PC for the user that has set this ip on the NIC, totally transparent to the "real" NIC that early have the IP address. i want to say you that i have read a little and this question for you is part of my investigation :) . Thanks in advance guys.

webster82
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Re: How to recognize and block if used a fixed ip address??

Fri May 20, 2016 10:52 am

There is no way to tell from the user's traffic if the IP address has been fixed or issued by DHCP. Consequently there is no way to drop it.

ski
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Re: How to recognize and block if used a fixed ip address??

Sat May 21, 2016 1:25 pm

It sound for me, this could only be solved on the client machine, not on the network devices. For the routers/switches/firewall/server, an IP is just an IP, they do not carry about whether it is assigned dynamically or statically. You could use come scripts on the client machine where, if the ip address is not assigned by DHCP, it shuts down / disables the interface.

zyklon
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Re: How to recognize and block if used a fixed ip address??

Sun Jun 05, 2016 6:29 pm

Thanks to both for your answers. It is clear for me that is the client who handle this kind of situation.

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