I have a compact machine, which can be physically equipped with only one
ethernet controler (no usb-ethernet possible since it doesn't support
usb. I'm thinking about converting it into a "home-use router/web
testing server" becouse it consumes the same amount of power as a
lightbulb :P

The question is - can I route the signal from my ISP using this machine
with one ethernet controller, a switch and miles of the ethernet cable?

i'd be grateful for any hint

MM

Mack Maverick wrote:
> The question is - can I route the signal from my ISP using this machine
> with one ethernet controller, a switch and miles of the ethernet cable?
concerning ADSL it is possible. the DSL data the modem sends is no IP
based. so hook yr DSL modem directly to the switch and hook the router
to the switch, too.
it's not the optimal way but it sure works.

if somehow u really need to have a second IP simply put an alias on eth0.


HTH
Matt

Mack Maverick wrote:

> The question is - can I route the signal from my ISP using this machine
> with one ethernet controller, a switch and miles of the ethernet cable?

I did it once, as a proof-of-concept - routing between two networks shared
on a single wire.

1. You need to configure the computer to have access to ISP.
2. Add an IP alias to the eth card with non-conflicting private address (one
of 10.x.x.x, 192.168.x.x or 172.16.x.x). The card should have TWO IPs
from now on
3. Enable FORWARDING. This should toss packets between nets.
4. Setup MASQUARADE (for dynamic ISP IP) or SNAT (for static ISP IP) working
that way:

Masquarade/NAT packets coming from local network going out via eth0.

Example for static IP:

iptables -t nat -A POSTROUTING -s YOUR-PRIVATE-NETWORK -o YOUR_NIC
-j SNAT --to-source YOUR-IP-AT-ISP

HTH
--
Pawel Kraszewski

In the Usenet newsgroup alt.os.linux.gentoo, in article
<dhj0hg$3pj$1@nemesis.news.tpi.pl>, Mack Maverick wrote:

>I have a compact machine, which can be physically equipped with only one
>ethernet controler (no usb-ethernet possible since it doesn't support
>usb. I'm thinking about converting it into a "home-use router/web
>testing server" becouse it consumes the same amount of power as a
>lightbulb :P

I have light bulbs from 4 Watts to 250 Watts in normal use, and there is
a 400 Watt security light that is occasionally used. That's a pretty
large spread. ;-)

Look at the newsgroup 'comp.os.linux.networking' for a thread titled
"Router Recommendations" where we discuss the relative costs. Briefly,
I use an old 386SX-16 that was once a laptop, without a display or
keyboard, and it takes about 30 VA. For a year, that's 263 KWH, and
costs about US$19.30 a year. If you have a 150 Watt desktop, the
consumption would be five times higher - 1315 KWH and in my case
US$96.50.

>The question is - can I route the signal from my ISP using this machine
>with one ethernet controller, a switch and miles of the ethernet cable?

From a security standpoint, the key is the switch. This will separate
the local packets from those for the ISP at only a minor loss of
bandwidth. The drawback is that the broadcast packets may still make
it through the switch, and seeing this traffic may annoy the ISP.
It would be better to use two NICs, but this can work. At the same time,
as a personal opinion - I do not like to run anything except the firewall
code on the firewall. Extra code running is extra code that _could_ be
exploited.

Old guy

Mack Maverick wrote:

> I have a compact machine, which can be physically equipped with only one
> ethernet controler (no usb-ethernet possible since it doesn't support
> usb. I'm thinking about converting it into a "home-use router/web
> testing server" becouse it consumes the same amount of power as a
> lightbulb :P
>
> The question is - can I route the signal from my ISP using this machine
> with one ethernet controller, a switch and miles of the ethernet cable?
>
> i'd be grateful for any hint
>
> MM
If your computer has ANY available pci slots (is your ethernet on a pci
card or built into the motherboard?) there ARE dual network pci cards
made (but not cheap) so maybe you could do that if you really need separate
physical networks.

The alias IP suggestions on a single network port made by others will work
(I didn't know about that...learn something new everyday!).