Re: Network Probs (was Re: Firewall issues)

On Wed, 11 Jun 2003, jdow wrote:

> Two cards with the same MAC address is deadly. How many other such
> situations exist on the network? This condition will lead to misdirected
> and lost packets. So if there is a way to change the MAC address of
> those cards do so.
> {^_^}
> 

Whoa..... no need to light the fires of fear yet.  You can have dozens
of network cards with the same MAC address *as long as they are on 
separate networks*.   Let me rephrase that; the only time you cannot have
two cards with the same MAC address is if they are on the same network.
MAC address are only visible on the local network; once a packet traverses
a router, the next device downstream sees the MAC address of the router
as the source, and so on.  Sun machines use a MAC address in the PROM 
for all network interfaces; I have worked with Sun boxes with up to
16 network interfaces all with the same MAC address.   No problem as each
interface was on a different network.  

- rick warner