Re: tlug: Dial-up - IMPOSSIBLE!

[Scott Stone <sstone@example.com>]

On Sun, 4 Oct 1998, Karl-Max Wagner wrote:

> > 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.

Or, use mgetty to answer the modem lines - mgetty takes care of proxyarp
for you - I'm not sure if it does this on its own or if it's passing a
commandline arg to pppd that takes care of it, but it does.  If you have
pppd and mgetty both [properly] installed, all you need to do is add a
line to /etc/inittab to have an mgetty respawn on the modem port in your
default runlevel, and then you can dial-in to it.

--------------------------------------------------
Scott M. Stone <sstone@example.com, sstone@example.com>
               <sstone@example.com>
Head of TurboLinux Development/Systems Administrator
Pacific HiTech, Inc (USA) / Pacific HiTech, KK (Japan)
http://www.pht.com		http://armadillo.pht.co.jp
http://www.pht.co.jp	        http://www.turbolinux.com


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