It's related to this question: Is 802.1x port security enforces IP uniqueness

If you have 802.1X port security can you change a MAC address of your device (to some other unused MAC address)? Will it trigger reauthentication? Will this be prohibited?

The same question for IP address. Can you change your IP address to some other unused IP address? What will happen? Will it trigger reauthentication? Will this be prohibited?

  • AS @HAL mentioned in his reply, that is true. And with 802.1x you can spoof your mac and obtain a new ip address via dhcp but you will still have to authenticate/login with your credentials.
    – user4565
    Commented May 23, 2016 at 20:09

1 Answer 1


And as was said in the other question, 802.1x is a layer-2 protocol. It is unaware of any layer-3 protocol(s). Changing your MAC can have several outcomes depending on the particular setup, ranging from nothing at all to permanent disabling of the port until an admin clears it. In all likelihood it would trigger reauthentication and be blocked until authenticated.

IP addressing happens above 802.1x. As such, it has no say in the matter. Address management and security must be managed by other means.

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