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Date:      Tue, 13 Jul 1999 00:33:33 -0400 (EDT)
From:      "Crist J. Clark" <cjc@cc942873-a.ewndsr1.nj.home.com>
To:        data@dreamhaven.net (Bryce Newall)
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: "arplookup failed xxx.xx.xx.x failed: host is not on local network"
Message-ID:  <199907130433.AAA07586@cc942873-a.ewndsr1.nj.home.com>
In-Reply-To: <Pine.NEB.4.10.9907121827340.37787-100000@ds9.dreamhaven.net> from Bryce Newall at "Jul 12, 99 06:52:18 pm"

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Bryce Newall wrote,
> Greetings once again,
> 
> I've seen this thread on the mailing list archives, but I'm not sure what
> to do here.  We have 2 machines set up at a local ISP.  The machines are
> called calico and manx, and I'll explain how the network is currently set
> up:
> 
> * We have 4 Class C's, 166.70.64, 166.70.73, 166.70.74, and 166.70.75.
> 
> * We also have a single IP in the ISP's address space, 204.228.135.145.
> 
> * calico is the "router" machine.  It has 2 ethernet adapters, xl0 and
> xl1.  xl0 is ifconfig'd as 204.228.135.145 and uplinks directly to the
> ISP's switch.  xl1 downlinks to a hub, where the other machine, manx, is
> connected.
> 
> * The ISP told us to use a subnet mask of 255.255.255.128 for the IP in
> their space, so we have:
> 
> xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         inet 204.228.135.145 netmask 0xffffff80 broadcast 204.228.135.255
> 
>   They also told us to use a subnet mask of 255.255.255.0 for the .1 IP's
> of our 4 Class C's, and 255.255.255.255 for the rest, so we have, for
> example:
> 
> xl1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         inet 166.70.64.1 netmask 0xffffff00 broadcast 166.70.64.255
>         inet 166.70.64.10 netmask 0xffffffff broadcast 166.70.64.255
>         inet 166.70.64.11 netmask 0xffffffff broadcast 166.70.64.255
>    (etc.)
> 
> * calico's 2nd ethernet card is ifconfig'd with several IPs in the
> 166.70.64 IP space, including 166.70.64.1.  It also is ifconfig'd as
> 166.70.73.1, 166.70.74.1, and 166.70.75.1.
> 
> * manx is ifconfig'd with all addresses in the 166.70.74 and 166.70.75
> subnets (i.e. .2-.254).  (We haven't used 166.70.73 yet.)  It also has 3
> IPs in the 166.70.64 IP space, of which the first is configured with a
> 255.255.255.0 netmask.  All the rest are 255.255.255.255, so we have:
> 
> xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>         inet 166.70.64.200 netmask 0xffffff00 broadcast 166.70.64.255
>         inet 166.70.64.203 netmask 0xffffffff broadcast 166.70.64.255
>         inet 166.70.64.206 netmask 0xffffffff broadcast 166.70.64.255
>         inet 166.70.74.2 netmask 0xffffffff broadcast 166.70.74.255
>         inet 166.70.74.3 netmask 0xffffffff broadcast 166.70.74.255
>   (etc.)
> 
> Here's the problem:  With the setup outlined above, manx is generating
> these messages every few seconds, over and over again:
> 
> Jul 12 19:00:17 manx /kernel: arplookup 166.70.74.1 failed: host is not on
> local network
> Jul 12 19:00:17 manx /kernel: arplookup 166.70.75.1 failed: host is not on
> local network
> 
> I don't understand, because 166.70.74.1 and 75.1 *are* on the local
> network.

But the interface does not know that. You gave all addresses a netmask
of 0xfffffff. Try to show which alias on manx's xl0 interface shares a
local net with either of those addresses. You can't; none do.

> They're one hop away from manx, to be exact.  When I first
> noticed the problem, I thought perhaps the netmasks I had configured on
> calico for 166.70.64.1, 74.1, and 75.1 (255.255.255.0 for each) were
> incorrect, so I changed them to 255.255.255.255.  That took care of the
> arplookup problem, but then created another problem:  Nothing on manx with
> a 166.70.74 or .75 IP could be reached from the outside!  Or even from
> calico.  The 166.70.64 IP could be reached, but none of the others, so I
> had to put the netmasks back the way they were.  So everything works now,
> but I'm still getting that arplookup error.
> 
> Any suggestions on what I may be doing wrong?

I suggest each machine have one alias that can access the whole subnet
it is on (address subnets, not physical nets or a "wire"). Go back to
calico's orignial setup with,

xl1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet 166.70.64.1 netmask 0xffffff00 broadcast 166.70.64.255
        inet 166.70.64.10 netmask 0xffffffff broadcast 166.70.64.255
        inet 166.70.64.11 netmask 0xffffffff broadcast 166.70.64.255
   (etc.)
        inet 166.70.73.1 netmask 0xffffff00 broadcast 166.70.73.255
	inet 166.70.74.1 netmask 0xffffff00 broadcast 166.70.74.255
	inet 166.70.75.1 netmask 0xffffff00 broadcast 166.70.75.255

Then, do the following on manx,

xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet 166.70.64.200 netmask 0xffffff00 broadcast 166.70.64.255
        inet 166.70.64.203 netmask 0xffffffff broadcast 166.70.64.255
        inet 166.70.64.206 netmask 0xffffffff broadcast 166.70.64.255
        inet 166.70.74.2 netmask 0xfffffe00 broadcast 166.70.74.255
        inet 166.70.74.3 netmask 0xffffffff broadcast 166.70.74.255
   (etc.)
        inet 166.70.75.2 netmask 0xffffffff broadcast 166.70.75.255
        inet 166.70.75.3 netmask 0xffffffff broadcast 166.70.75.255
   (etc.)

Now, calico can talk to any address on 166.70.64/24, inet
166.70.73/24, 166.70.74/24, or 166.70.75/24 through the '.1' address
on each.

As for manx, the 166.70.64.200 address can reach anywhere on
166.70.64/24, and 166.70.74.2 anywhere on 166.70.74/23 (i.e. both the
166.70.74/24 and 166.70.75/24 nets). You said 166.70.73/24 is not
being used, so nothing is there.

Now, every net can be reached by a _single_ address (no more, no
less) on each machine. You should not get error message. I think that
should do it. 
-- 
Crist J. Clark                           cjclark@home.com


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