Since 5.0 NetBSD supports changing the MAC address. Add a link-layer address to an Ethernet: # ifconfig sip0 link 00:11:22:33:44:55 Add and activate a link-layer address: # ifconfig sip0 link 00:11:22:33:44:55 active This should give some idea: ifconfig bridge0 create ifconfig bridge0 up ifconfig vr0 up brconfig bridge0 add vr0 ifconfig tap0 create sysctl -w net.link.tap.tap0=00:00:de:ad:be:ef ifconfig tap0 up brconfig bridge0 add tap0 Now you can get an ip if from dhcp with the fake MAC: dhclient tap0 ## See also * [[!template id=man name="ifconfig" section="8"]]