Re: tlug: Dial-up - IMPOSSIBLE!

[karlmax@example.com (Karl-Max Wagner)]

> Once a dial-up connection is established, from home, I can ping, slogin,
> telnet, FTP etc. from the dial-up client to the dial-up server.  I cannot,
> however, make a connection to any other machine (local or otherwise).
> Upon looking at the logs of a machine on the local subnet of the server
> diring a ping or other type of connection, I see ICMP redirect requests
> coming from the gateway of the subnet.  It's as if the packets go out from
> the client, through the dial-up server yet the server does not respond to
> anything destined for the dial-up client.

Very neat observation :-). That's your problem. Gonna explain:
if a packet destined for one of your dial-up ports floats along
the ethernet to which your dial-up server is connected, the
dial-up server should grab it off the net and hand it over to
the respective dial-up port. That's what you need but what's not
happening at the moment. In order to get that working you have
to use proxyARP. In order to do so you have to add additional
entries into your kernel routing table. 

You do this with the following command:

arp -s <IP-addr_of_dialup_port> <eth?_HWaddre> pub

The HWaddr is the hardware address of your ethernet interface
linking you to your LAN ( the stuff you get behind HWaddr when
doing an ifconfig ). The other parameter is the IP address of
your dial-up port. The pub neans "publish". It MUST be there. It
says that the dial-up port IP addresses, and not only, the
machine's own address, are linked to the hardware address of the
ethernet port. In that way the packets for your dial-up ports
are grabbed off the ethernet by means of the HWaddress, and,
once inside the gateway machine, are routed to the respective
dial-up port ( it is, of course, necessary to provide the proper
routes with appropriate "route add .... gw ...." commands.
However, this seems to have been done ).

That should do it.

================================================================
"It was hell. They knew it.          Karl-Max Wagner
  But they called it                 karlmax@example.com
    W-I-N-D-O-Z-E"
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