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Antsle NIC MAC addresses keep changing!!

I'd like to use DHCP for my antsle br0 (currently only using the 1 network interface), but every time I restart the unit, it gets a different MAC address.   (My network monitor (FingBox) also keeps griping that a new device has joined the network)

Is there any way to make the physical NICs keep the same MAC address?

Are you sure you are not seeing the MAC address of a virtual machine behind the bridge? Because the hardware MAC of the Antsle itself should not be changing. Can you post some examples of the MAC you are seeing? If it starts with 52:54:00 then it is almost certainly one that is being generated by libvirt, not a hardware MAC.

Attached are some screenshots of what my network reports as its MAC address when I reboot (and it connects to the network).

The antsle unit has a static IP of 192.168.86.9

Currently, if I get on the antsle console and do ip addr, it shows:

8: br0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 3a:d3:1a:0b:7a:ea brd ff:ff:ff:ff:ff:ff
inet 192.168.86.9/24 brd 192.168.86.255 scope global br0
valid_lft forever preferred_lft forever
inet6 2600:8804:6100:5df:38d3:1aff:fe0b:7aea/64 scope global mngtmpaddr dynamic
valid_lft 67746sec preferred_lft 67746secinet6 fe80::ae1f:6bff:fe49:836c/64 scope link
valid_lft forever preferred_lft forever

 

That MAC matches the first screenshot:

SmartSelect_20181208-140450_Fing - Copy.jpg

Uploaded files:
  • SmartSelect_20181208-140450_Fing-Copy.jpg
  • SmartSelect_20181208-140519_Fing-Copy.jpg
  • SmartSelect_20181208-140618_Fing-Copy.jpg
  • SmartSelect_20181208-140704_Fing-Copy.jpg
  • SmartSelect_20181208-140735_Fing-Copy.jpg

Indeed, all of those MAC addresses have bit 1 set and bit 0 cleared in the left-most octet, which means "locally administered unicast".

IOW, they are probably all generated for a virtual interface. The Antsle, like most virtualization platforms, has in internal software bridge (switch) that the various VM's connect to. The external Ethernet is also connected to the same bridge. That is how VM's are connected to the outside world.

Apparently, by default a bridge device (e.g. our br0) will get assigned the lowest MAC of all the interfaces connected to it, but the virtual interfaces are generated semi-randomly. In fact it seems the bridge MAC can change as VM's are started and stopped! This is something I did not know even though I've used Linux bridging a few times.

The fix is to manually assign a MAC, such as the one from the actual phsyical NIC connected to the bridge. I'm not familiar enough with Gentoo to know how to do this (I'm a Debian guy), and also I'm not sure how the configuration files interact with AntMan. I suggest contacting support to see if they can help, but maybe this will get you started:

https://forums.gentoo.org/viewtopic-t-941916-start-0.html

It might be good for Antsle to set it up that way by default if they are going to support DHCP, or else allow us to set the MAC address from AntMan. Time for a feature request I guess.

Thanks, @bobh.  That points me in a direction!

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