Issues with IP address when changing MAC address

My guess is that you are in an environment where you automatically get an IP via DHCP and that you manually set an IP to always use the same IP without contacting the administrator of the DHCP server.

That means what the same IP would be handed out via DHCP and that it would be used by your computer, resulting in an UP conflict.

The solution is to go to the network admin, explain why you want a fixed IP and have him or her add that to the reservations list. That means that you will always get your same (fixed) IP via DHCP.

If you did not do this but instead just configured it manually in the DHCP's pool range then you are causing network problems. As an admin I would respond to that by blocking the device which caused these problems followed by a nice talk explaining why not to do it this way.

This might be why your MAC is blocked.

Trying to work around it by spoofing your MAC is not the right solution. Go talk to your network guy or gall.

Hennes

Posted 2014-02-22T13:32:58.717

Reputation: 60 739

Ok as u told, I will talk to the admin this time. I need a permanent solution. Thanks for the advice. – Debesh Bar – 2014-02-23T03:02:44.210

As a comment, most enterprise level multi service WiFi devices will block devices that are mac-spoofing (Device goes from MAC A, IP A, to MAC B, IP A within a short period of time as a defense system. This could be what is causing your DHCP to fail. Why are you MAC spoofing in the first place? – George Spiceland – 2014-02-25T07:18:45.850

He is spoofing his mac because "My original MAC address is blocked on the network". Something which I assume is because he used a fixed IP without asking for it in the first case. This should be resolved after he talked to his network admin. – Hennes – 2014-02-25T17:33:28.467

Issues with IP address when changing MAC address

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