SUMMARY : Ethernet addressing - duplication?

From: Oleg Chaikovsky (
Date: Thu Sep 09 1993 - 02:01:52 CDT

To all,

Thanks for the quick and timely replies. Apparently this behavior is correct. The easiest answer came from Steve Pomush at AMGEN who writes:

> This is correct. It turns out that MAC addresses are a commodity. In order
> to save addresses, Sun puts the MAC address into the EEPROM and all
> the SBus ethernets get there addresses from the same place. The logic is
> that no two interfaces will be on the same subnet, so the same address
> can be used over on a different subnet.

So , as long as the ethernet interfaces are on different cable segments, there are no problems. If you want the different interfaces on the same ethernet segment (cable), you need to use ifconfig to establish a new MAC address.
(ifconfig le1 8:0:20:...)

Many thanks to the following: (Ian MacPhedran) (Brett Lymn)
amgen!usops!spomush@uunet.UU.NET (Steve Pomush)
Jason.Hargis@PII.COM (Jason Hargis) (Birger A. Wathne)
Casper Dik <>
Christoph Rothlin (
Mike Raffety <> (Joel Shandelman) (Steve Swaney) (Ron Henderson)
bobr@houston.nam.SLB.COM ( Bob Reardon )
Gene Rackow <>
Andrew Benson <> ( Bill Hunter)
Frank Peters <fwp@CC.MsState.Edu>
J M Thompson <> (Michael Baumann)
Patrick O'Callaghan <> (R. Michael Van Dyk)

Thanks again,

Oleg Chaikovsky
Sun/Mac Systems Manager
Rockwell International - Downey, CA
America Online:

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