Let's suppose that my computer is connected to WIFI and also computer of my collegue is connected to the same WIFI.

Now, I change my IP address on WIFI interface (using ifconfig) to the same as my collegue.

Does it mean that I capture his packets? Why, why not?

  • It's WiFi, so you can (most likely) see all their traffic already. In the case of enterprise wifi, each associated client has their own security key(s). So what your NIC can hear (either from the AP or the other clients) is encrypted and unusable.
    – Ricky
    Jun 6, 2018 at 20:18

1 Answer 1


Sorry, you'll have to find some other way to eavesdrop on your "colleague." :-)

The AP, being a layer 2 device, forwards traffic based on MAC address. IF you change your IP address, you won't change your MAC address. Now, if and when your PC generates an ARP reply, the upstream router will update its ARP table. But now your colleague will no longer get data, so she'll know that something is up. Her computer may also generate an ARP reply, in which case she will get the traffic instead of you. Your two computers will "fight" for the data, and likely neither one of you will receive enough useful data.

This assumes you maintain your association with the AP as you change your address. Depending on the client, that might not happen.

  • don't worry I am CS student that try to understand many things. It seems to be something like ARP flood.
    – user47846
    Jun 9, 2018 at 20:21

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