SUMMARY: Multiple Ethernet Cards

From: David Procter (
Date: Wed Nov 30 1994 - 05:21:28 CST

Hello Managers,

Original mail:
> Sparc10/512, Solaris 2.3, one additional ethernet card.
> As mentioned in recent mail (and in the FAQ) the second card takes on
> the same physical address as the main board interface.
> I have assigned two different (Class A) IP addresses to the interfaces.
> Can I connect them to the same twisted-pair hub/repeater ? If not, how
> should I choose a new physical address ? Is there a command for displaying
> the physical addresses of all the machines currently connected so that I can
> avoid a clash ?
> As you will have realised I am a novice at this type of configuration :)
> so any additional pointers to information (we don't have ftp at the moment)
> would be very useful. I know that 'subnet' refers to IP addressing but does
> it also cover the physical connection of machines ?

     Thank you for your replies. My notes follow :

1. The physical address must be different for each interface in the network and
   can be changed using "ifconfig le1 ether a:b:c:d:e:f:g".

3. "/usr/sbin/arp -a" lists *some* of the physical addresses on the network.
   'getethers' is a pd tool used for find physical addresses, available for
   SunOS 4.1.3.

3. Solaris 2.x allows multiple IP address for each hardware interface.

4. Recommended reading : Internetworking with TCP/IP, Volume I, by Comer.

5. I'm sure that one person mentioned that the SBus card gives better
   performance than the motherboard interface because it's data-buffered. I
   can't find the message so apologies to the one who sent it.

     I wanted to connect an ISDN router (allocated a Class C address by RIPE
NCC) and decided to use a dedicated (2nd card) in one of the Sparcs. The two
machines had been using a different Class C address. Instead of purchasing
a second repeater to link the two I wanted to investigate the option of
Multiple cards.

     I've now got the money for a second repeater. Although it would have been
possible to use just one repeater I've decided to play safe and use a different
physical network.

Thanks to :-

Mike Rembis <>
Louis M. Brune <>
Peter Samuel <>
Dan Frenette <>
Norbert Saazer <saazer@grado.CV.COM>
Eckhard R ggeberg <>
Casper Dik <>
Tom Crummey <>
one other ?




David Procter Digital Communications Development,
                                            Sony United Kingdom Ltd.,
                                            Pencoed Technology Centre,
Tel: +44 (0)1656 867541/2 Pencoed,
Fax: +44 (0)1656 863914 Mid Glamorgan.
E-mail: CF35 5HZ. Wales, UK

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