Broadcast traffic?

[Samuel Rydh]

On Fri, Dec 19, 2003 at 02:18:36PM -0500, Romeyn Prescott wrote:
> I have been running MOL 0.9.68 on YDL 3.0 as installed by YDL for 
> months.  While *I* do not experience network difficulties, my Network 
> Manager came to me the other day because he discovered that my ASIP 
> traffic was being seen in places it has no business being, given the 
> server to which I was connected.
> 
> After further investigation, he determined that packets originating 
> from the MOL installation on my box were being encoded as if they 
> were from the Ethernet Broadcast Address (FF:FF:FF:FF:FF:FF)!!
> 
> Why would this be happening?  As far as I know, I'm using the Sheep driver.

Well, it won't happen for TCP/IP traffic with the tun driver
(the recommended and configuration).

The problem is the sheep_net driver (both TCP/IP and AppleTalk are
affected). Packets sent from linux to MOL will unfortunately be
transmitted on the wire too. There is no way these packets can be
filtered out without custom kernel modifications.

To address this problem (in 0.9.69), I have made sure that the
destination address of these spurious packets are changed to the
mac address of the linux machine. This guarantees that
these packets are dropped by switches. In particular, no other
machine on the network will ever see them.

It is only the linux->MOL direction that is affected. All other direction
(MOL->linux, MOL<->externl host) should work without side effects.

So, the solution is:

	- Use the tun driver (for TCP/IP)
	- Upgrade MOL

/Samuel