[lug] Dial up domain and routing question
nate at natetech.com
Thu Mar 15 11:47:08 MST 2001
"Atkinson, Chip" wrote:
> I'm trying to work out a weird scheme where I can dial in to another machine
> and use only one of the 5 available IP addresses.
> Here's the desired setup --
> Remote machine(s): DSL with 8 static IPs (5 available for use)
> local machine: Dial into remote machine and use one of the 5 available
> static IPs.
> Without subnetting and dividing up the 8 IPs, is this possible? I was
> thinking I could alias two IPs on the machine with the modem and then
> redirect all traffic to one of the aliased IPs to the dialed in machine.
So you want to set up a ppp link that uses one of the available IP's on
your subnet? Sounds simple enough ('cause I've had that set up here for
a couple of years now at home. Heh heh...) unless I misinterpreted what
you're trying to do?
In my case, there's a modem hanging off of one of the machines here for
me to be able to dial in to home with... and I wanted to be assigned a
static IP that was NOT the IP of the machine I was dialing into for the
First, you'll need IP Forwarding compiled in and turned on in your kernel...
echo 1 > /proc/sys/net/ipv4/ip_forward
Also in /etc/ppp/options (on my Debian machine) I added:
(So the local machine would proxy arp requests for the IP of the modem
Then I also had to add an /etc/ppp/options.ttyS1 file with :
Where telluride is the machine that has the modem attached, and ppp is
the name of the DNS/hosts entry for the IP I want handed out on the
modem line. I think you can also do this like:
Is what I described what you're trying to do?
I also tweaked a number of other ppp settings for my environment, but
these were the key ones to getting the dialup working with its own IP
address. Other stuff like the ms-dns setting in the options file (hands
out the DNS server properly if I dial in with a Windows machine) and
others were just for convenience. (Setting the MTU to 512, et cetera.)
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