Subject: Re: /dev/tap and tcpdump don't go together very well?
To: Johnny Billquist <>
From: Greg Troxel <>
List: current-users
Date: 04/09/2007 10:42:42
Johnny Billquist <> writes:

> This all reminds me of another thing.
> Are there any way, or plans to be able to, change the mac address of
> an ethernet interface in NetBSD? I don't think there is, but I might
> have missed something.

I think someone just needs to write device-indenpendent support and then
modify various drivers.

> When doing stuff like Olaf is doing here, changing the MAC address
> might be desireable (in his case if he wants his PDP-10 to run TOPS-20
> with DECnet enabled, since DECnet wants specific MAC addresses on
> interfaces...)

I don't think the tap's Ethernet address is relevant.  The PDP-10's
emulated Ethernet interface (how modern to plug one of those in, instead
of CHAOSnet or an IMP....) will have an address, but that's controlled
entirely within the emulator.  Packets with that source address are
generated, and then written to /dev/tapN to make them show up on the
virtual interface on the host.