Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 17 Mar 2012 12:38:12 -0500
From:      "David DeSimone" <fox@verio.net>
To:        <freebsd-net@freebsd.org>
Subject:   Re: invalid MAC addresses?
Message-ID:  <20120317173811.GI6640@verio.net>
In-Reply-To: <20120317172227.Horde.tDn5QKQd9PdPZLpDyq9bvcA@avocado.salatschuessel.net>
References:  <20120317172227.Horde.tDn5QKQd9PdPZLpDyq9bvcA@avocado.salatschuessel.net>

next in thread | previous in thread | raw e-mail | index | archive | help
Oliver Lehmann <oliver@FreeBSD.org> wrote:
>
> when I update the BIOS of my new AM3+ Mainboard, The MAC address of
> my re0 card gets changed from c8:60:00:60:3b:c6 to ed:0b:00:00:e0:00
> With this change, no communication with any other FreeBSD system is
> possible.

The mac address ed:0b:00:00:e0:00 is a multicast mac (first octet has
bit 1 set), which means it is not suitable for use with a unicast IP.
Other systems when they see your ARP reply with a multicast mac, are
going to treat this as an error, and ignore your ARP.

You could work around the problem by forcing the mac to something else,
(such as 22:44:66:11:22:33) and then other systems will believe that the
mac is acceptable for unicast.

However, it's clear that your NIC's eeprom has been programmed with an
incorrect mac setting, which it sounds like you are already trying to
fix.

-- 
David DeSimone == Network Admin == fox@verio.net
  "I don't like spinach, and I'm glad I don't, because if I
   liked it I'd eat it, and I just hate it." -- Clarence Darrow


This email message is intended for the use of the person to whom it has been sent, and may contain information that is confidential or legally protected. If you are not the intended recipient or have received this message in error, you are not authorized to copy, distribute, or otherwise use this message or its attachments. Please notify the sender immediately by return e-mail and permanently delete this message and any attachments. Verio, Inc. makes no warranty that this email is error or virus free.  Thank you.



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20120317173811.GI6640>