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Date:      Thu, 15 Aug 1996 19:49:16 +0300 (IDT)
From:      Nadav Eiron <nadav@cs.technion.ac.il>
To:        Michael Ryan <mike@NetworX.ie>
Cc:        questions@freebsd.org
Subject:   Re: Two Ethernet cards in one machine on same IP network
Message-ID:  <Pine.SV4.3.91-heb-2.04.960815194501.13664B-100000@cs.technion.ac.il>
In-Reply-To: <ECS9608141829B@NetworX.ie>

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On Wed, 14 Aug 1996, Michael Ryan wrote:

> I've a system (FreeBSD 2.1R) with two NICs: WD8013 and NE2000.
> I want to plug both of them into the same IP network,
> on the same cable.
No can do!!! I don't have any intimate knowledge of the implementation of 
IP in FreeBSD, but the first (well, O.K. among the first) thing I learned 
about IP is that a machine MUST have at most one interface on an IP network.
That's part of the reason subnetting was invented!
I can't imagine why you'd like two cards on the same ethernet cable, but 
if you really do, give one of them a netmask of 255.255.255.255. This 
would cause it to be used just to receive packets for its address (I 
think it will never transmit. Am I wrong on that???).

> 
> I ifconfig the WD8013 (ed0) first, and it goes fine.
> When I ifconfig the NE2000 (ed1), I get an error message
> as follows.
> 
> # cat /etc/hosts
> 194.9.12.7      h1
> 194.9.12.8      h2
> # ifconfig ed0 inet h1
> # ifconfig ed1 inet h2
> ifconfig: ioctl (SIOCAIFADDR): File exists
It's telling you that you already have an interface to that network.

> 
> When I then do "ifconfig ed1" the parameters (IP address,
> netmask and broadcast address) are fine, but I can't ping
> the IP address (h2), even from the machine itself.  The
Because the ifconfig failed.

> routing table shows that the address (194.9.12.8) is reached
> via link#1 -- which is sort of correct, as that's the
> interface to the 194.9.12.0 network, but that's not what
> I expected (link#1 == ed0).
> 
> Any ideas?
> 
> 
> Thanks,
> Mike
> <mike@NetworX.ie>
> ---
> 
> 
> 
> 
You're welcome,
Nadav



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