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Date:      Tue, 13 Feb 1996 11:07:21 -0800 (PST)
From:      Zarathustra <jef@akasha.punk.net>
To:        freebsd-questions@freebsd.org
Subject:   proxy-arp and ppp
Message-ID:  <199602131907.LAA14541@akasha.punk.net>

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I can't seem to manually add arp entries.  When I try to proxy-arp for another
IP address, I get the following message:

[akasha] [10:28] [/tmp] [51] SU > arp -s 204.212.160.254 00:00:21:12:62:90 pub
cannot intuit interface index and type for 204.212.160.254


This is a FreeBSD 2.1 machine.  It gives the same message no matter what
IP address I specify.  I've read through arp.c but until I find some good
documentation on the ins and outs of routing sockets it won't do me much good.
I've tried compiling the kernel with ARP_PROXYALL but that didn't seem to
change anything.  BTW, what does it do?  The kernel source wasn't very
enlightening.

The reason I need to do this is because I'm using this machine as a 'client'
to dial into a ppp 'server' on an otherwise isolated subnet.  The client
is connected to the rest of the internet and is responsible for maintaining
connectivity to the server.  The addresses used for the ppp connection are
taken from the subnet on which the client resides due to scarcity of IPs on
the server side subnet.  Because of this, the client needs to proxy-arp for
the addresses used for the ppp connection.  Without proxying, packets 
outbound to the rest of the internet which originated with the server ppp
machine never can be responded to, because the return address is that of
the server-side ppp interface, which the rest of the net thinks is found
on the client's subnet.

Normally (in a sane world) the client and server roles would be reversed,
and the server ppp process would automatically proxy for the ppp addresses.
However, in this case, the machine connected to the internet *must* be the
one which performs the dialing out.

Both machines run FreeBSD 2.1 and ijppp.


Can anyone tell me why adding the arp entry doesn't work, or perhaps a
better way of solving this problem?


Thanks!

Jeff Schnitzer



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