Ethereal-users: Re: [Ethereal-users] Capture with Gbps NIC

Note: This archive is from the project's previous web site, ethereal.com. This list is no longer active.

From: Guy Harris <guy@xxxxxxxxxxxx>
Date: Thu, 17 Jul 2003 16:41:37 -0700

On Thursday, July 17, 2003, at 4:36 PM, Ian Schorr wrote:

I'm assuming you're wanting to know if there is something general about gigabit ethernet that would prevent promiscuous mode on <some platform>. I'm not aware of any general limitations of libpcap on any platform that prevent promiscuous capture on, generally, gigabit NICs.

Or perhaps he wants to know whether capturing in promiscuous mode on a gigabit network would supply so much traffic that Ethereal would have a problem keeping up. If so, the answer is probably "yes" if the wire is running at full speed. Of course, promiscuous mode is only partially relevant to that; what really matters is the rate of traffic, but if you're on a gigabit hub, *if* such things exist, or if you're on a switched port that's been set up as a mirrored port, that means you could see more traffic than you'd see on a regular switched port (and, in fact, if you're on a mirrored switch port, you could see more traffic than will fit on the gigabit link between you and the switch, in which case the *switch* will drop packets that won't fit on the link).