Reply To: WAN MAC Address Spoofing – How To?

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Hi athling,

Thank you very much for the reply. I did as you suggested, with the ETH00 interface set to a static IP address. In the Post Boot script I put:

# Startup Script
ifconfig ETH00 down
ifconfig ETH00 hw ether 00:80:48:BA:d1:30
ifconfig ETH00 up

In the above example, the MAC address is only an example.

After changing the Post Boot script to Status: Enabled I then saved the script and rebooted the ZS machine from the Web GUI. The ZS machine reboots. Now I see the MAC address change is persistent both in the text console with “N”, and on the PC (after unplugging and replugging the Ethernet cables between the PC, switch and ZS machine to refresh the arp tables) and by looking at arp -a on the connected PC. The connected PC can log in to the ZS machine via the Web admin GUI again with the new MAC address.

So far so good; but not good enough though…

As I mentioned in my OP, the ISP provides me with an address via the DOCSIS cable modem using DHCP, and does not tolerate a changed MAC address for the host/router connected to the cable modem.

So this is the nasty (IMO) part of this problem…

Changing the MAC address on the WAN port connected to the cable modem, which provides an IP via DHCP, doesn’t work. Changing the MAC address using the Post Boot script occurs too late.

The ISP sees an ‘incorrect’ MAC address, and will not give me a DHCP lease (those bastards). So I need to spoof the MAC address before the DHCP client daemon for the WAN port on the ZS machine is started. Actually it would be better to spoof the MAC address as soon as the interface is brought up – as early as possible. Maybe a change in the bootloader (Kernel option) or in the Pre Boot script?

Hmm…. Any suggestions?

Thanks & Best Regards, David