Re: DSL router and networking - Help!
Hi Philip,
On Fri, 11 Jan 2002, Phillip Deackes wrote:
<snip info. about service to be purchased>
> I use Samba on the Linux box so that the Windows machine can print to the
> Linux printers, and squidso that the Windows machine can access web
> sites.
>
> In my Linux PC I have two network cards. One card is connected to thecable
> modem, the other to a small 4 port Netgear hub. When I get the SpeedTouch
> Pro I intend removing the second card on the Linux box since the STP can
> be plugged into my hub. What I would like to do is to continue using the
> networking I have already setup for file sharing and printing (though
> there will obviously be some reconfiguring with there being a single nic
> in the Linux box.
IMHO the best way to do this is to keep the two NIC's in your PC. Leave
one connected to your hub and connect the other one to the STP. Then use
IP masquerading. This is made easy in Debian by using the ipmasq
Debian package.
apt-get install ipmasq
Provided there is a default route configured through the ethernet
interface connected to the STP, and the IP address, netmask and broadcast
for the ethernet interface connected to your hub are correct for your
local net, ipmasq will set up firewalling and masquerading automatically
for your net.
Any machine connected to your hub and configured to use your Debian box as
the default gateway will have access to the Internet. You will have the
option to use squid on the Linux box as a web proxy, or access the web
directly. Use the IP address of the ethernet interface on the Linux box
which is connected to the hub as a default gateway on all machines
connected to the hub. All machines will be able to access all Internet
services, not just the Web.
Services provided to your local net by the linux box should not be
affected by any of this.
You will also need to set up name services so that machines on your
internal net can resolve names on the Internet. You can either use your
ISP's nameserver(s) or run your own local nameserver on the Linux box.
The latter solution would give a performance advantage because query
results are cached, avoiding the net traffic caused by repeat queries, but
you can leave this upgrade for later.
> The quick setup guide for the STP uses DHCP as a default which would be
> great apart from the fact I can't see how I would be able to network the
> two machines if the IP addresses keep changing.
On your Linux box, set up DHCP only for the interface connected to the STP
and leave the interafce connected to the hub configured with a static
address. Edit /etc/network/interfaces and check the entry for the
ethernet interface connected to the hub, assuning it's eth0:
iface eth1 inet static
address 192.168.1.1 (for example)
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
Add (or change) the entry for the interface connected to the STP as
follows, assuming it's eth1:
iface eth1 inet dhcp
Of course, this assumes that your ISP will be assigning your IP address
and routing info. via DHCP, which might not be the case:
> Looking through the manual, I see sections for all sorts of protocols.
> Eclipse Internet tell me to use RFC2364 PPPoATM VC Encapsulation
> Multimode AutoModulation. The nearest I can find in the STP manual is
> either PPoA-to-PPTO relaying or PPP & IP routing. Which should I use?
Can't help you there, sorry. Take this up with the people who sold you
the STP and with your ISP. Once you sort out how to connect the STP to
your ISP, we can sort out how to get the Debian IP layer to play with
them.
> I would imagine I would need to allocate a static IP address to each
> machine (ideally what I already use - 192.168.1.1 and 192.168.1.0)
> this would surely mean that the networking would just carry on
> working.
Don't use the address 192.168.1.0 as a host address. It's the first
address on the network 192.168.1.0/24 (netmask 255.255.255.0). Being the
first address, it's reserved to refer to the whole network. Use e.g.
192.168.1.2 instead. If the address of your private net is 192.168.0.0/16
instad of /24 (netmask 255.255.0.0 instead of 255.255.255.0), then the
first address is 192.168.0.0 and technically 192.168.1.0 is useable as a
host address. However, accepted practice is that addresses on 24-bit
boundaries such as 192.168.0.0, 192.168.1.0, 192.168.2.0 etc. should be
reserved in case the network 192.168.0.0/16 needs to be divided
(subnetted) into smaller nets e.g. 192.168.0.0/24, 192.168.1.0/24 etc.
Best regards, good luck and don't hesitate to come back with any more
questions,
| George Karaolides 8, Costakis Pantelides St., |
| tel: +357 99 68 08 86 Strovolos, |
| email: george@karaolides.com Nicosia CY 2057, |
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