Changing MAC address disconnect network

Hey,
I've been trying to change my MAC address by running the follow:

Code:

---

#ifconfig eth0 down

---

Code:

---

#ifconfig eth0 hw ether "NEW_MAC_ADDRESS"

---

Code:

---

#ifconfig eth0 up

---

running the following results in the same issue:

Code:

---

#macchanger -r eth0

---

I've run those commands both on bridged network and NAT, using VM VirtualBox
any help will be appreciated