[Mageia-discuss] home network using broadband router

WALKER RICHARD richard.j.walker at ntlworld.com
Wed Mar 7 00:41:02 CET 2012

OK, you have two PCs on a private network with addresses in the range

You reported only 192.?.?.? If that is accurate then the addresses are
public, meaning if I knew what they are then I could reach them from

Forgive me if I tell you things you already know. IP networks are
defined by their address. My home network, for example, has been
defined by me to occupy only addresses in the range to These are only 256 of the 65536 addresses available. My
network has no awareness of the possibility of other addresses because
I have not configured it. My router's configuration web address is, but that is not within my network, so even though I am
physically connected to it, its address is inaccessible to me.

Technically, my network's routing table has no information on how to
reach and by definition (it is private, remember) there is
no way to reach it via the public network - it simply does not exist

So, if your router and each of your PCs share the first two octets of
the address (192 and 168) and your network mask is then
any address in the range to (or
thereabouts) is valid for your network.

Let's check your network mask so we know the extent of your private
network. Use the ifconfig command in a console (you might need to be
root for this) and look for the line in the output for your eth?
interface which looks something like this;

inet addr:  Bcast:  Mask:

You can see on mine that the mask is which means that
only the eight bits of the final octet can be used on my network for
unique addresses - 0 to 255. So what is your network mask?

On 06/03/2012, e-letter <inpost at gmail.com> wrote:
> On 06/03/2012, mageia-discuss-request at mageia.org
> <mageia-discuss-request at mageia.org> wrote:
>> Message: 3
>> Date: Tue, 6 Mar 2012 00:47:01 +0000
>> From: WALKER RICHARD <richard.j.walker at ntlworld.com>
>> Quick answer; yes
>> man ifconfig should get you started. From memory you can set an
>> address for an ethernet card with something like;
>> ifconfig eth0
>> That implicitly brings up the connection.
>> This much is already working for you as you say both PCs can reach the
>> internet. So let's take a step back. I don't want you to "publish"
>> your PC addresses, but if they are both on the same network then they
>> should both have addresses in the private network ranges. The most
>> common on routers are;
>> 10.?.?.?
>> 192.168.?.?
> command terminal 'ifconfig' returns value for eth1, '192...', but not
> '10...'.
>> Can you configure your router? Do you know if it has a web-based
>> configuration address? If you haven't come across this before, this is
>> a "web page" generated by your router which provides access to its
>> configuration by means of forms on web pages. It is normally accessed
>> by entering the address in your browser, but this cannot easily work
>> if your PC and your router are on different networks, with different
>> address ranges. For example, the router might be on and
>> your PC is on a.b.x.x  where a and b are NOT 192 and 168.
> yes, there is a configuration address 'http://192...' accessible via
> web browser.
>> Let us take one more step back. When you configured your network on
>> each computer (using MCC?)  did you opt for manual or automatic (via
>> DHCP) configuration of the network address? That, I think, is the key
>> starting point.
> automatic dhcp. To check, the command 'drakconnect' was used to
> activate the network configuration process; the default is automatic
> ip (bootp/dchp) connection protocol
>> If it is manual then you chose the addresses and typed them in. If it
>> is automatic (via DHCP) then they will have been allocated by EITHER
>> your router (which seems unlikely given the trouble your having) OR by
>> your ISP, and that means they are permitting you to have more than one
>> public address for your location AND that the address really is
>> public; if I knew your address I could probe your network - that is
>> potentially highly risky and is why the common practice, in these
>> parts, is for each subscriber to get one public address and have the
>> modem/router provide NAT for private networks on the premises.
> I think the ip address is determined by the isp; if the router is
> switched off and then on, a new ip address is assigned.
>> I hope I haven't confused the issue. Let me re-state the important
>> questions:
>> 1. Are your PC addresses similar to each other?
> yes, they differ by a digit
>> 2. Are they in the private network range? (10.?.?.? or 192.168.?.?)
> yes, 192...
>> 3. Do you have the make and model of your router? (yes/no will do for
>> now.)
> yes

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