internet connection sharing issue

[inenewbl]

Hi all. I am currently staying in a hotel with my colleague and our room has
only 1 lan connection. I connected my notebook to the lan connection. My
notebook is also connected to my colleague's notebook using adhoc wireless.
Initially i set my notebook wireless network with an ip of 192.168.2.1 and my
colleagues wireless ip as 192.168.2.2 with the gateway set as 192.168.2.1. I
have also added a static ip for dns address to my colleague notebook. My
colleague could connect to my notebook via wireless adhoc however he could
not access the internet. Finally i had to enable ics on my lan connection
after which my wireless is assigned an ip of 192.168.0.1 by winxp. I then had
to change my colleague wireless ip to 192.168.0.2 with the gateway
192.168.0.1. Hence my question is why must i enable ics checkbox before my
colleague could access internet. Before enabling ics, i have the correct
settings already, when my notebook receive data from my colleague notebook
headin for internet it shld go thru the lan connection gateway since that is
the default route. Thks in advance.

 

[John B]

"0.1" and "2.1" should be considered "gateway" addresses, as you have
discerned. Therefore you must refrain from assigning any gateway address to
your computer; the gateway is probably a router downstairs in the hotel
lobby. No two ip HOSTS (a.k.a. "nodes," or "leaf items") that have any
chance of "seeing each other" can have the same ip address. Yet hosts must
be informed of the nearest gateway address, so that they might direct
INTERNET petitions to that gateway, for eventual connection through the
world's conglomeration of IP routers.

To deviate a bit, NETWORKS have addresses, too. In reality, any such
"address" is really a band (or collection) of addresses that span the subnet
defined by your subnet mask. But for the sake of simplicity, your local
("private," by the way) network may be described as 192.168.0.0. You are
almost certainly engaging Class C addressing, typified by a 255.255.255.0
subnet mask. This is very common "INTRANET" addressing (not internet)
addressing, when you're inside the hotel LAN. The gateway demarcs the
intranet from the internet.

To answer your question, I would say that your "near" computer is acting as
a BRIDGE, and apparently you enable that bridge only if (necessarily, but
not sufficiently) ICS (internet connection sharing) is enabled. Thus your
near computer has two ethernet connections within it, ON THE SAME SUBNET.
Routers connect different subnets; bridges connect segments that share a
common subnet.

Any corrections to this explanation, from resident experts on this usegroup,
are welcome.

 

[John B]

To make my admonition against misuse of gateway addressing more clear, any
computer LAN device may be assigned a single primary IP address from any
UNUSED ip address within a subnet collection...EXCEPT the lowest (which is
reserved for subnet identification); the highest (which is reserved for
broadcasting; IOW all nodes listen to this address by default); and one
other address within any subnet, which is defined as the "gateway address"
by the router that defines any subnet.

Every subnet has a router. Every router has an "inside address," also known
as the gateway address. Though you might get into the router and change
this address, it is generally set as ".1" by default. Don't mess with this
convention, unless you want to risk confusion and malfunction.

Every computer LAN device SHOULD also be informed of a secondary IP address
that IS the gateway address. Failure to do so will preclude INTERNET
access, while not precluding INTRANET access.

Redundant use of addresses, such as you seem to have done, take all bets off
the table. The anomalous results fall out from the peculiarities of the
equipment design.

 

[Chuck [MVP]]

Hi all. I am currently staying in a hotel with my colleague and our room has
only 1 lan connection. I connected my notebook to the lan connection. My
notebook is also connected to my colleague's notebook using adhoc wireless.
Initially i set my notebook wireless network with an ip of 192.168.2.1 and my
colleagues wireless ip as 192.168.2.2 with the gateway set as 192.168.2.1. I
have also added a static ip for dns address to my colleague notebook. My
colleague could connect to my notebook via wireless adhoc however he could
not access the internet. Finally i had to enable ics on my lan connection
after which my wireless is assigned an ip of 192.168.0.1 by winxp. I then had
to change my colleague wireless ip to 192.168.0.2 with the gateway
192.168.0.1. Hence my question is why must i enable ics checkbox before my
colleague could access internet. Before enabling ics, i have the correct
settings already, when my notebook receive data from my colleague notebook
headin for internet it shld go thru the lan connection gateway since that is
the default route. Thks in advance.

Every computer doesn't, by default, act as a NAT gateway. That's a result of
running ICS. Defining a second computer, to use the IP address of the first
computer as its default gateway, doesn't make the first computer a gateway
either. So assigning IP addresses on 192.168.2.0/24 to various computers won't,
by itself, provide Internet service for any computer.

What's the WAN address of the ICS server? If it's on 192.168.0.0/24, you won't
be able to use ICS.
<http://nitecruzr.blogspot.com/2005/05/ics-is-ok-but-you-can-do-better.html>
http://nitecruzr.blogspot.com/2005/05/ics-is-ok-but-you-can-do-better.html

--
Cheers,
Chuck, MS-MVP 2005-2007 [Windows - Networking]
http://nitecruzr.blogspot.com/
Paranoia is not a problem, when it's a normal response from experience.
My email is AT DOT
actual address pchuck mvps org.

 

[Jack \(MVP-Networking\).]

Hi
The two computer are on different subnet thus it is like they are on two
independent Networks.
To mitigate such a connection you need a Router.
ICS is Software Router.
Since you have only Lone LAN connection out it has to be set this way.
Jack (MVP-Networking).

 

[John B]

Thanks for clarifying this. I had it wrong about ICS...it routes different
subnets, as you say.
For which versions of WinXP does this work, may I ask? Home, Pro, Media
Center?