BB Black ethernet issue

Hi Tim,

I’m just looking at this and the issue seems to be a duplicate MAC address (fe80::caa0:30ff:fead:19c9) on your network – all computers on the same subnet need different MAC addresses. These should never be the same and what probably happened is you moved your BBB to a different port/switch on your network and the caching mechanism (arp tables) has kept it around. There is probably a better way to do this but you can reboot your networking equipment (maybe including some computers too) and reboot your BBB. I think this will fix itself after some time too.

The other possibility is you have two devices with the same MAC address. If that is the case ‘ifconfig’ will tell you what they are (WIndows has it’s own commands) and then you would need to see if you can change it to something different on the BBB (or the other computer so they are unique). I forget the command and don’t know if it is supported on the BBB but this is most likely not your issue.


The funny thing is that that message shows up whether a cable is plugged in or not. I think it’s reading it’s own MAC address.

Although, I just tested it again and I can’t recreate that particular message.

I flashed the eMMC to the latest Angstrom release and it still does the same thing. I guess I’ll have to wait until I get a serial cable.

I am still having issues with the Ethernet port. I now have a serial cable so I can get to u-boot. I’m not sure how to test the PHY though. Anyone have any suggestions?

Also, I get the messages about a duplicate IPv6 address whether I have a cable plugged in or not. As Glen mentioned, the fe80 IPv6 address is based on the MAC address. I think the PHY is talking to itself.

What happens if you run …

$ dhclient -v eth0

… with an ethernet cable plugged in?

Sorry, I just read through the rest of the thread. If you give it a manual address and then ping it, does it respond? Sounds like your eth0 is acting like a loopback… which is bizarro. I would be curious if it exhibits the same behavior with and without a cable attached. Sounds like you might have a bad cable, but I’m guessing you probably tried another one.

When I set an IP manually ping returns destination unreachable.

When I try to use DHCP it times out waiting for a response. I’ve used two different cables on the same switch port. I’ll try a different switch port next time.

FYI, I got an RMA from beagleboard.