topic Re: Is it possible to change an interface MAC address?? in Firewall and Security Management

Is it possible to change an interface MAC address??

Allen_Fambro — Thu, 18 Jul 2019 08:25:29 GMT

Hello,

Is it possible to change the physical MAC address of an interface on the gateway (Gaia R80.30 3200 appliance)?? Troubleshooting a DHCP assigned IP address for the interface and want to change the MAC to prove the issue is on the DHCP server. I know I could just use a different interface as well but that only changes the last digit in the MAC. I'd like to use a totally different MAC.

I tried changing it below but it doesn't seem to stick. Any assistance would be greatly appreciated. Thanks.

Re: Is it possible to change an interface MAC address??

G_W_Albrecht — Thu, 18 Jul 2019 11:52:14 GMT

Please consult Gaia Administration Guide R80.20 p.62:

On the Ethernet tab:

• Select Auto Negotiation, or select a link speed and duplex setting from the list.

• In the Hardware Address field, enter the Hardware MAC address (if not automatically received from the NIC).

Caution: Do not manually change the MAC address unless you are sure that it is incorrect or has changed. An incorrect MAC address can lead to a communication failure.

Re: Is it possible to change an interface MAC address??

Allen_Fambro — Thu, 18 Jul 2019 14:46:31 GMT

I figured it out. You cant seem to use the GUI however I was able to "spoof" the MAC using ifconfig via the command line. Not sure if this would have survived a reboot though as I was only doing it for troubleshooting purposes...

1 - ifconfig eth1 down
2 - ifconfig eth1 hw ether 94:9A:A9:84:75:45
3 - ifconfig eth1 up

Just for clarification, this should only be done for troubleshooting requirements. This should not be standard practice, etc...

Thanks.

Re: Is it possible to change an interface MAC address??

PhoneBoy — Fri, 19 Jul 2019 05:56:15 GMT

Definitely anything done via ifconfig won't survive a reboot and/or msy be overridden if you make any configuration changes in clish/WebUI.