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Date:      Wed, 2 Oct 1996 16:20:06 +0300
From: (Petri Riihikallio)
To:        Richard J Kuhns <>
Subject:   Re: IP forwarding not working
Message-ID:  <v01530500ae780e1f43ef@[]>

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>OK, how about trying
>arp -s lonely_mac ether_addr pub
>on your gateway machine, where "lonely_mac" is the hostname for the Mac,
>and "ether_addr" is the colon-seperated 6 field ethernet address of the
>card in the gateway.  This tells the rest of the net that your gateway
>machine will respond to requests for "lonely_mac" even tho the host address
>is not it's own.
>Check out arp(8) for more info.

Thanks for your input.

If I understand arp(8) correctly, the setup you suggest would cause all ethernet
packets addressed to lonely_mac being accepted by the FreeBSD box as well. This
is not allowed and I get a "writing to a routing socket: File exists"-error.

At the moment the ethernet works correctly. All packets addressed to lonely_mac
are accepted by the Mac alone. All packets the Mac generates, either addressed
to the FreeBSD box or the Internet, are received by ed0. The problem is that
the FreeBSD doesn't forward the packets to ppp0.

The whole setup looks like:

     |                    |
  +-----+            +---------+
  | Mac |            | FreeBSD |
  +-----+            +---------+
                       | ISP |-->Internet

I think you were thinking of the proxyarp option to pppd. It causes pppd to
add an arp entry for the IP address at the other end of the ppp link. I tried
it but it didn't work because my IP addresses are not in the same subnet as
the ISP's PPP interface. I don't know whether that option would activate the
packet forwarding.

If you have any more thoughts please let me know.



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