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From: Softweyr LLC <softweyr@xmission.com>
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Subject: Re: routing problem I think? help please
To: questions@freefall.freebsd.org
Date: Tue, 3 Dec 1996 14:56:31 -0700 (MST)
Cc: robert@chalmers.com.au
In-Reply-To: <199612031647.IAA28001@freefall.freebsd.org> from "owner-questions-digest@freefall.freebsd.org" at Dec 3, 96 08:47:34 am
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> 
> I have a router (Ascend 50) connedted by ISDN to the local ISP. Over this is
> piped the college traffic. The network works fine, and is rock solid. It
> operates on its own C class network. 
> 
> Now, I ran up FreeBSD on a small PC, just to fiddle about, and installed
> it as a different C class. One of our valid networks, so there is no
> problem there. It is connected to the network that carries the traffic
> for the rest of the net out through the router.
> 
>                               ............existing network, works fine....
> ........internet...[router]../\
>                                 \.........the temporary box, different C class.
> 
> So, when I start up the baby freebsd, it returns the error message at the
> network startup, IP Address already in use by 00:xx.xx.xx.xx  (ether card
> number). The number returned is that of the router !!!!  It's telling
> me that the router is using the baby-pc's ip address, when of course it
> isn't. It's using its own, and an entirely different C class at that.

Well, if it is *only* on the "entirely different C class", then it cannot
possibly talk to your FreeBSD machine, and your FreeBSD machine could not
talk to it.  What is most likely happening is that your Ascend 50 has an
"alias" on *your* class C network assigned to it's ethernet interface and
you just *happened* to pick the same address.  Pick a different IP address
in the same class C network and try again.