Those quad ethernet cards support one MAC address per PHY, or they can operate as a Cisco EtherChannel or probably other similar technologies used to bond ethernet links, depending upon how you configure it and your switch.
I sent the below message to someone else on the list in private, thinking that they might benefit from some further explaination, but also thinking that most people subscribed to this list would have a solid understanding of how modern ethernets work, and thus would not benefit from the post. Obviously I was wrong, there appear to be lots of people on this list that don't grok ethernet, so below is that message for the benefit of everyone. -----Original Message----- From: Jeff S Wheeler [mailto:[EMAIL PROTECTED] Sent: Friday, March 16, 2001 11:44 PM To: Mike Fedyk Subject: RE: arpwatch and more An ethernet switch won't send frames to "multiple ports". Ethernet switches can broadcast, they can unicast, and some new layer3 switches can multicast IP "efficiently", but if your switch sees the same MAC address on several interfaces, one of them is going to get blocked (if you have spantree), or the switch will just learn the new interface, and frames would go to the wrong interface, but not to both. - jsw -----Original Message----- From: Tim Kent [mailto:[EMAIL PROTECTED] Sent: Monday, March 19, 2001 12:50 AM To: debian-isp@lists.debian.org Subject: Re: arpwatch and more I guess that means you have to keep those quad Ethernet Sun cards away. Tim. ----- Original Message ----- From: "Marc Haber" <[EMAIL PROTECTED]> To: <debian-isp@lists.debian.org> Sent: Saturday, March 17, 2001 7:50 PM Subject: Re: arpwatch and more > On Fri, 16 Mar 2001 13:05:06 -0800, Mike Fedyk <[EMAIL PROTECTED]> > wrote: > >On Fri, Mar 16, 2001 at 09:24:56PM +0100, Marc Haber wrote: > >> Please be aware, though, that the MAC address is trivial to forge > >> nowadays. > >Hmm, how does a switch deal with the same mac address coming from two ports > >at the same time? > > It will probably flap. MAC address forging will only work if the host > that owns the forged MAC is switched off or disabled in some other > way. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
