From owner-freebsd-isp  Sun Dec  9  8:40:39 2001
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Date: Sun, 9 Dec 2001 11:40:25 -0500 (EST)
From: Jim Weeks <jim@siteplus.net>
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To: Rowan Crowe <rowan@sensation.net.au>
Cc: freebsd-isp@FreeBSD.ORG
Subject: Re: arplookup
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On Sun, 9 Dec 2001, Rowan Crowe wrote:
 
> Just a warning that this will break connectivity to IPs in that block of
> 65535 IPs that are *not* on that LAN.
> 
> For example, if your IP is 1.1.100.3 and your netmask is 255.255.255.0,
> your LAN has 255 local hosts, and everything else is routed via the
> gateway. If you change it to 255.255.0.0, then your LAN has 65535 local
> hosts, and everything else is routed via the gateway.
> 
> This means that if you try to communicate with (say) 1.1.200.1, it will
> fail, because your machine assumes it's on the LAN, when it's *really*
> outside of that network, and can only be reached via the gateway.
> 
> Coming full circle, setting that hostmask may actually cause similar or
> identical ARP errors on other machines, because there will be ARP requests
> coming from your machine for IPs that *are not* on the LAN (but your
> machine thinks they are)

Full circle indeed!  This brings us back to the original problem, why
aren't these requests coming through the gateway in the first place.  I
haven't had a strait answer to that question yet.  Any enlightenment would
be appreciated.

Thanks,
--
Jim Weeks


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