ICS questions and confusion

[DWalker]

I had ICS set up and working fine for a couple of years on a desktop
computer (the laptop computer in the house used the desktop computer's DSL
connection).

I upgraded the desktop computer from 2000 to XP, and I ran into two of the
same issues again. I'd like some comments on these two, if anyone else is
bothered by the same things that confuse me.

First, when you're on the host computer, and you want to enable sharing of
the Internet connection, the Advanced tab of the connection has the ICS
checkbox that says: "Allow other network users to connect through this
computer's Internet connection". I have always found that wording
confusing.

It doesn't make it clear which connection icon you should enable this
checkbox on -- the connection that's cabled to the DSL modem/router, or the
wireless PCI card, which is the connection THROUGH which the "other network
users" actually GET to this host computer.

Yes, I want to "allow other network users to connect through this
computer's Internet connection", but from a data-modeling standpoint, that
is an attribute of the entire host computer, not an attribute of either of
the two Ethernet connections on the host computer. Or maybe it is an
attribute of both of the Ethernet connections involved in the Internet
connection sharing.

Whenever I had trouble with ICS before, I would futz around with these
settings and I could never remember which connection was supposed to have
the checkmark. Even reading other explanations of how to set up ICS (like
at practicallynetworked.com), didn't make it completely clear. Maybe it's
just me.

Comments?

Secondly, when I had intermittent problems with the laptop accessing the
Internet in the past, I tried to disable and re-enable this ICS checkbox.
But I always got the error message that said some other connection on the
network already had the required address 192.168.0.1. I understand
completely about this address, and I know that it's given to the LAN
connection through which the other computers connect to this computer.

The problem is, the "other" connection on the network that already had
address 192.168.0.1 was the SAME ONE that Windows needs to give that
address to in order to re-enable ICS. Windows complains that the address
is occupied by the same adapter to which it wants to give that address to.
Isn't that stupid?

[I eventually discovered that I could re-enable a working ICS by disabling
the LAN connection that goes to the DSL router, turning off the ICS
checkbox, turning the ICS checkbox back on, then re-enabling the LAN
connection. I couldn't turn the ICS checkbox back on untless I first
disabled the LAN connection, and that avoided the stupid message above.
Has anyone else had to do this to unstick a balky ICS?]

When you go to turn on ICS, the wording here again is confusing. It says,
and I quote:

"When Internet Connection Sharing is enabled, your LAN adapter will be set
to use IP address 192.168.0.1."

The phrase "your LAN adapter" is poorly chosen. I have two LAN adapters --
one connects to my DSL modem/router, and the other is my wireless PCI card
that the laptop connects to this computer with. This phrase makes it sound
like I only have one LAN adapter. Again, I get confused which one is going
to get address 192.168.0.1 -- the one that's connected to my DSL router, or
the PCI wireless card?

Finally, the message goes on to tell you to turn on let the other computers
on the network get their addresses automatically. I had some trouble with
this, and finally set the single "other computer[]" on my network to use
the static address 192.168.0.50. What's the benefit of turning on DHCP for
the other computer? Is it just to make sure that I know to set up the
other computer with the same subnet with the right mask?

Anyway, let me know if anyone agrees or disagrees with my complaints and
confusion here.

Thanks.

David Walker

 

[DWalker]

My own followup question, sort of a general ICS "how-to" question:

In ICS, if you have an Ethernet connection to the DSL modem/router,
should that connection be in the same 192.168.0.x subnet as the host's
Ethernet connection (192.168.0.1) that connects the clients (this is the
wireless PCI card in my case)?

I take it the host's wireless PCI card that the client uses to connect,
is the one that gets the 192.168.0.1 address. My DSL modem/router was
originally shipped with address 192.168.0.1, so I changed it to
192.168.0.254. I put the Ethernet connection that's cabled to the DSL
modem/router at 192.168.0.50.

Should I put the DSL modem/router's internal IP address, and the local
Ethernet card in a different subnet from 192.168.0.x?


Thanks.

 

[Chuck]

My own followup question, sort of a general ICS "how-to" question:

In ICS, if you have an Ethernet connection to the DSL modem/router,
should that connection be in the same 192.168.0.x subnet as the host's
Ethernet connection (192.168.0.1) that connects the clients (this is the
wireless PCI card in my case)?

I take it the host's wireless PCI card that the client uses to connect,
is the one that gets the 192.168.0.1 address. My DSL modem/router was
originally shipped with address 192.168.0.1, so I changed it to
192.168.0.254. I put the Ethernet connection that's cabled to the DSL
modem/router at 192.168.0.50.

Should I put the DSL modem/router's internal IP address, and the local
Ethernet card in a different subnet from 192.168.0.x?


Thanks.

David,

Since your Host to client LAN uses ICS, you have to keep 192.168.0/24 on that
LAN. The LAN connecting your router to host has to be another subnet
altogether.

It would really be better for everybody if you would work on your problem,
instead of putting in a workaround (ie NetBEUI) and recommending it to
everybody. Alternate protocols like IPX/SPX and NetBEUI won't really help the
situation in the long run.
<http://nitecruzr.blogspot.com/2005/07/windows-networking-and-alternate.html>

There is really no reason why a supported solution like NetBIOS Over TCP/IP
can't work in your case.

I haven't seen any previous posts from you in this forum. Or did you post long
ago, or maybe use a different nym?

 

[DWalker]

David,

Since your Host to client LAN uses ICS, you have to keep 192.168.0/24
on that LAN. The LAN connecting your router to host has to be another
subnet altogether.

It would really be better for everybody if you would work on your
problem, instead of putting in a workaround (ie NetBEUI) and
recommending it to everybody. Alternate protocols like IPX/SPX and
NetBEUI won't really help the situation in the long run.
<http://nitecruzr.blogspot.com/2005/07/windows-networking-and- alternate
.html>

There is really no reason why a supported solution like NetBIOS Over
TCP/IP can't work in your case.

I haven't seen any previous posts from you in this forum. Or did you
post long ago, or maybe use a different nym?

I wasn't recommending anything to anybody; I really just installed
NetBEUI to make sure to my satisfaction that the wireless cards were
properly making the peer-to-peer connection. I would prefer to take the
NetBEUI back out, and I understand the issues you bring up in your Web
page.

I called this a followup because it was a reply to my own message of a
few minutes previous. Were you replying to both my messages? Other
than those two, I haven't posted in this newsgroup before; I'm usually
in the SQL Server newsgroups.

Question: WHY does the LAN connection that connects my router to the
host have to be on a different subnet than the 192.168.0.x one? And
where is that documented in all the how-to's on ICS, and in the
Microsoft documentation? I have never seen that documented.

It doesn't HAVE to be on a different subnet, because I was running the
pervious setup for years (with the host being Windows 2000) and it
worked fine. It doesn't work now that I upgraded the host to Windows
XP.

If you saw my other post, do you have any comments on the issues I
raised there, other than NetBEUI? Is the same-subnet issue the reason
for the system telling me that another connection in the network is
already using 192.168.0.1 (which, if that's the case, is an incorrectly
worded error message. Just because another adapter is on the same
subnet, doesn't mean that another connection is already using
192.168.0.1.)

Thanks. I look forward to your comments.

David

 

[DWalker]

Chuck: I saw in KB article 308006 the instruction:

"If you are trying to configure Connection Sharing manually for a
connection, make sure that the home network adapter does not have ICF
enabled. If ICF is enabled, you must either disable it before you can
configure Connection Sharing on the external connection or use the
Network Setup Wizard to enable ICS. The wizard disables ICF on home
networking interfaces."

What's the "home network adapter"? That phrase is not defined in the
article. Does it mean the adapter that's connected to the rest of the
network inside the house? I configured ICS manually and also ran the
wizard, and in neither case was the firewall disabled on any of the
interfaces.

The KB article also says this:

"Verify the IP address on the shared connection to confirm that it is
obtaining an IP address from your ISP."

The DSL modem/router gets it IP address from the ISP, but my Ethernet
adapter that is cabled to this modem/router *can't* get its IP address
from the ISP. The ISP can only give the address to the modem/router
itself. This part might have been written a long time ago or maybe
applies to a different kind of connection. No wonder I'm confused, if
there is outdated information out there.

I'm not trying to be difficult, I'm just trying to get ICS set up to
work!

----

Since my DSL modem/router is a Qwest Actiontec 1524 with wireless
capability itself, if I turn on the wireless on the Actiontec and set up
the laptop to connect to that wireless instead of the desktop's wireless
PCI card, and turn off ICS on the desktop computer, will the laptop also
be on the same network as the desktop computer -- able to share folders
and the printer? Or do I have to "bridge" something to get this wto
work?

Thanks.

David Walker

 

[N. Miller]

I had ICS set up and working fine for a couple of years on a desktop
computer (the laptop computer in the house used the desktop computer's DSL
connection).

I upgraded the desktop computer from 2000 to XP, and I ran into two of the
same issues again. I'd like some comments on these two, if anyone else is
bothered by the same things that confuse me.

First, when you're on the host computer, and you want to enable sharing of
the Internet connection, the Advanced tab of the connection has the ICS
checkbox that says: "Allow other network users to connect through this
computer's Internet connection". I have always found that wording
confusing.

It doesn't make it clear which connection icon you should enable this
checkbox on -- the connection that's cabled to the DSL modem/router, or the
wireless PCI card, which is the connection THROUGH which the "other network
users" actually GET to this host computer.

Yes, I want to "allow other network users to connect through this
computer's Internet connection", but from a data-modeling standpoint, that
is an attribute of the entire host computer, not an attribute of either of
the two Ethernet connections on the host computer. Or maybe it is an
attribute of both of the Ethernet connections involved in the Internet
connection sharing.

The problem is, this isn't "data modeling", this is a hardware connection;
two hardware connections, really. Each connection has to be uniquely
identified. The one which connects to the laptop is separate from the one
which connects to the DSL modem.

Whenever I had trouble with ICS before, I would futz around with these
settings and I could never remember which connection was supposed to have
the checkmark. Even reading other explanations of how to set up ICS (like
at practicallynetworked.com), didn't make it completely clear. Maybe it's
just me.

Comments?

If you start with the notion of connections, and see that your "host"
computer has two of those, maybe it will make more sense? The connection to
the DSL modem is the one which will be shared.

Secondly, when I had intermittent problems with the laptop accessing the
Internet in the past, I tried to disable and re-enable this ICS checkbox.
But I always got the error message that said some other connection on the
network already had the required address 192.168.0.1. I understand
completely about this address, and I know that it's given to the LAN
connection through which the other computers connect to this computer.

The problem is, the "other" connection on the network that already had
address 192.168.0.1 was the SAME ONE that Windows needs to give that
address to in order to re-enable ICS. Windows complains that the address
is occupied by the same adapter to which it wants to give that address to.
Isn't that stupid?

Not really. There can only be one IP address 192.168.0.1 in the network. If
the "other" connection has that IP address, ICS can't assign it to the
network adapter in the "host" computer. No other connection in the network,
or the computer (two connections, remember?) should have that IP address,
or you can't re-enable ICS.

[I eventually discovered that I could re-enable a working ICS by disabling
the LAN connection that goes to the DSL router, turning off the ICS
checkbox, turning the ICS checkbox back on, then re-enabling the LAN
connection. I couldn't turn the ICS checkbox back on untless I first
disabled the LAN connection, and that avoided the stupid message above.
Has anyone else had to do this to unstick a balky ICS?]

It has been a long while since I used ICS. It sounds like you have both
network adapters set up in the 192.168.0.0/24 network; and ICS is finding
that some device already has the IP address which it wants to assign. Most
likely the modem has that address, so ICS will balk until you disable the
network connection to the modem.

When you go to turn on ICS, the wording here again is confusing. It says,
and I quote:

"When Internet Connection Sharing is enabled, your LAN adapter will be set
to use IP address 192.168.0.1."

The phrase "your LAN adapter" is poorly chosen. I have two LAN adapters --
one connects to my DSL modem/router, and the other is my wireless PCI card
that the laptop connects to this computer with. This phrase makes it sound
like I only have one LAN adapter. Again, I get confused which one is going
to get address 192.168.0.1 -- the one that's connected to my DSL router, or
the PCI wireless card?

At the time that was written, most people would have one Ethernet adapter,
and one dial-up modem. They just haven't gotten around to a re-write to
cover the contemporary situation. It helps me to think of the adapter which
has the Internet connection as the "Internet Adapter". The adapter to which
the laptop is attached should be considered the LAN adapter. Now, reading
that instruction again, which is the one that should get IP address
192.168.0.1? The "Internet Adapter"? Or the "LAN Adapter"?

While you have two network adapters, you really only have one "LAN
Adapter"; the other network adapter is the "Internet Adapter".

Finally, the message goes on to tell you to turn on let the other computers
on the network get their addresses automatically. I had some trouble with
this, and finally set the single "other computer[]" on my network to use
the static address 192.168.0.50. What's the benefit of turning on DHCP for
the other computer? Is it just to make sure that I know to set up the
other computer with the same subnet with the right mask?

The advantage of using DHCP is that you don't have to manually track which
device gets which IP address, how DNS is assigned, and so on. It really is
easier to use DHCP; but you have to be sure that the two network adapters
are in different IP address blocks, or DHCP can make a squirrelly situation
get squirrelier.

Anyway, let me know if anyone agrees or disagrees with my complaints and
confusion here.

To begin with, you can't have two different networks with the same network
address. Your Internet connection is a different network than your LAN.
Your two network adapters in your "host" computer must have different
network addresses. ICS always uses 192.168.0.0/24, assigning 192.168.0.1 to
the adapter in the ICS, or "gateway", computer. No other device connecting
to that computer can have that IP address, or ICS won't work. Because your
modem is at IP address 192.168.0.1, you will have a problem getting ICS to
work unless you can make some changes. Since you said that you can change
your modem IP address, I would suggest setting it to 192.168.1.1.

Next, you have to differentiate which network does what. That is where you
think of the network adapters as the "Internet Adapter", and the "LAN
Adapter". Having changed your modem IP address to 192.168.1.1, your
"Internet Adapter" should get an IP address from the modem; probably
192.168.1.2, but I don't really know. Which modem is it that you have? BTW,
if you couldn't change the IP address on the modem, you would have to
change it to bridge mode, or you could never get ICS to work.

Now that your "Internet Adapter" is properly configured, you can set up
ICS. When ICS asks which adapter to share, you will check the "Interenet
Adapter". When ICS wants to set the "LAN Adapter" to IP address
192.168.0.1, there will no longer be a conflict. You can let ICS handle
DHCP, now, and tell the laptop to obtain an IP address automatically. The
last time that I set up ICS, each successive computer connected to the LAN
obtained an IP address one higher than the last; the laptop would get
192.168.0.2. And so on.

Finally, is your modem truly a router? It can use DHCP to assign IP
addresses? If so, why not invest $10 - $15 for a switch? Instead of ICS,
let the router component of the modem handle IP address assignment. If the
modem can't do that, you should still be able to use a switch, and just set
the IP addresses of the computers manually, as a static LAN. Then you don't
need to run the "host" computer just to access the Internet.

 

[Chuck]

I wasn't recommending anything to anybody; I really just installed
NetBEUI to make sure to my satisfaction that the wireless cards were
properly making the peer-to-peer connection. I would prefer to take the
NetBEUI back out, and I understand the issues you bring up in your Web
page.

I called this a followup because it was a reply to my own message of a
few minutes previous. Were you replying to both my messages? Other
than those two, I haven't posted in this newsgroup before; I'm usually
in the SQL Server newsgroups.

Question: WHY does the LAN connection that connects my router to the
host have to be on a different subnet than the 192.168.0.x one? And
where is that documented in all the how-to's on ICS, and in the
Microsoft documentation? I have never seen that documented.

It doesn't HAVE to be on a different subnet, because I was running the
pervious setup for years (with the host being Windows 2000) and it
worked fine. It doesn't work now that I upgraded the host to Windows
XP.

If you saw my other post, do you have any comments on the issues I
raised there, other than NetBEUI? Is the same-subnet issue the reason
for the system telling me that another connection in the network is
already using 192.168.0.1 (which, if that's the case, is an incorrectly
worded error message. Just because another adapter is on the same
subnet, doesn't mean that another connection is already using
192.168.0.1.)

David,

I was replying to your earlier post also, and I was sort of in the process of
figuring it out when you posted the follow-up.

You CAN have the "router to host", and the "host to client", LANs in the same
subnet, but that requires that the ICS host become a bridge. ICS is a software
based NAT router, and routers work best when the different interfaces are on
separate LANs. And, if you want to use ICS, that means that the "host to
client" LAN WILL use 192.168.0/24. That's one of the "features" (limitations)
of ICS.

I agree with you that the message "some other connection on the network already
had the required address 192.168.0.1" is confusing. Not having seen your
network, I can't say for sure, but I'd be almost willing to bet that both the
connection to the router, and the connection to the client, are creating a
bridge. And since ICS insists on using 192.168.0.1 for its hosts LAN address,
it's having the problem there. If you setup the host as a bridge, you still
won't be able to use 192.168.0.1 anywhere else.

There are so many things about Microsoft Networking that are confusing. One of
the subjects I try to help with is Windows Networking and Network Neighborhood.
If I had a dollar for every time I've mentioned the Browser as a problem and
someone replies "My Internet connection is fine" or similar, I'd have a lot of
dollars.

The "Allow other network users to connect through this computer's Internet
connection" is relative to the host, and the Internet connection is the network
adapter that this computer uses to access the Internet. In order to share
Internet service, you have to have service. And that's the LAN that should not
be on the 192.168.0/24 subnet.

Anyway, if I had a dollar for every time I've thought how confusing their
documentation is, I'd have a hella lot of dollars. But that's one of the side
benefits of the MVP program, I now have a contact in Microsoft, and I can ask
him questions. And I have an avenue for suggesting documentation improvements
(ie KB articles). So instead of cursing the darkness, I'm now in a position to
light a couple candles. And I've lit a couple so far, and maybe I will get to
light some more during the next few months.

So, to your situation. I strongly recommend that you:
# Change your router LAN to another subnet, say 192.168.1/24.
# Identify the problem with Windows Networking in your laptop LAN, and restore
NBT / TCP/IP as the transport there.

Once you get everything working, then play with the features and fine tune
everything. Maybe figure out why it used to work with the router on the
192.168.0/24 subnet. But get it working first.

 

[Chuck]

Chuck: I saw in KB article 308006 the instruction:

"If you are trying to configure Connection Sharing manually for a
connection, make sure that the home network adapter does not have ICF
enabled. If ICF is enabled, you must either disable it before you can
configure Connection Sharing on the external connection or use the
Network Setup Wizard to enable ICS. The wizard disables ICF on home
networking interfaces."

What's the "home network adapter"? That phrase is not defined in the
article. Does it mean the adapter that's connected to the rest of the
network inside the house? I configured ICS manually and also ran the
wizard, and in neither case was the firewall disabled on any of the
interfaces.

The KB article also says this:

"Verify the IP address on the shared connection to confirm that it is
obtaining an IP address from your ISP."

The DSL modem/router gets it IP address from the ISP, but my Ethernet
adapter that is cabled to this modem/router *can't* get its IP address
from the ISP. The ISP can only give the address to the modem/router
itself. This part might have been written a long time ago or maybe
applies to a different kind of connection. No wonder I'm confused, if
there is outdated information out there.

I'm not trying to be difficult, I'm just trying to get ICS set up to
work!

----

Since my DSL modem/router is a Qwest Actiontec 1524 with wireless
capability itself, if I turn on the wireless on the Actiontec and set up
the laptop to connect to that wireless instead of the desktop's wireless
PCI card, and turn off ICS on the desktop computer, will the laptop also
be on the same network as the desktop computer -- able to share folders
and the printer? Or do I have to "bridge" something to get this wto
work?

Thanks.

David Walker

David,

KB308006 appears to be referring to ICF / ICS, ie ICS pre SP2. And, as Norman
points out separately, ICS was originally written for sharing dial-up access,
which means that any mention of a "LAN" referred to the network between the host
and the clients. ICS was never intended to be used for sharing broadband
Internet service from a router (ie a LAN), just from a modem (broadband or
dialup, with a modem you don't have a LAN there).

I'm pretty sure that "Verify the IP address on the shared connection to confirm
that it is obtaining an IP address from your ISP." refers to a modem directly
connected to the computer, not a modem connected to a router connected to the
computer. The router gets an IP address, on its WAN side, from the ISP. You
assign the IP address to the router on its LAN side, and either assign the IP
addresses to the clients, or let the router assign their addresses.

If you connect the laptop to the router directly, you can put both the desktop
and the laptop on the same subnet with the router, and they will connect
directly. No, you won't have to setup a bridge or anything. That is so much a
better solution.
<http://nitecruzr.blogspot.com/2005/05/ics-is-ok-but-you-can-do-better.html>

 

[DWalker]

Subject: Re: ICS questions and confusion
Newsgroups: Microsoft:microsoft.public.windowsxp.network_web
To: "N. Miller" <[email protected]>

Hi, Nick, thanks for the reply (I was out for a few days). Please see
my responses below.

The problem is, this isn't "data modeling", this is a hardware
connection; two hardware connections, really. Each connection has to
be uniquely identified. The one which connects to the laptop is
separate from the one which connects to the DSL modem.

What I meant by "a data modeling standpoint" is just that it's an
attribute of the whole host, not an attribute of one of the connections.
When I do data modeling for customer data, I have to make sure that
things are stored at the right "level" -- customer data at the customer
level, account data at the account level, etc. I claim that "allow
other network users to connect through this computer's Internet
connection" is an attribute of the computer, not of one of its
connections.

If you start with the notion of connections, and see that your "host"
computer has two of those, maybe it will make more sense? The
connection to the DSL modem is the one which will be shared.

Right, that does help, although the wording says "allow other network
users to connect through this computer's Internet connection", not
"allow other network users to connect through this connection".

Not really. There can only be one IP address 192.168.0.1 in the
network. If the "other" connection has that IP address, ICS can't
assign it to the network adapter in the "host" computer. No other
connection in the network, or the computer (two connections,
remember?) should have that IP address, or you can't re-enable ICS.

I *know* that the system can have only one connection at 192.168.0.1.
What I'm *saying* is that the only thing in the whole network that has
address 192.168.0.1 is the very same Ethernet connection that ICS is
going to set up with address 192.168.0.1. I know that my computer has
two connections.

[I eventually discovered that I could re-enable a working ICS by
disabling the LAN connection that goes to the DSL router, turning off
the ICS checkbox, turning the ICS checkbox back on, then re-enabling
the LAN connection. I couldn't turn the ICS checkbox back on untless
I first disabled the LAN connection, and that avoided the stupid
message above. Has anyone else had to do this to unstick a balky
ICS?]

It has been a long while since I used ICS. It sounds like you have
both network adapters set up in the 192.168.0.0/24 network; and ICS is
finding that some device already has the IP address which it wants to
assign. Most likely the modem has that address, so ICS will balk until
you disable the network connection to the modem.

No. Although the modem defaulted to 192.168.0.1, I changed it to use
192.168.0.254 because I knew that ICS needed 192.168.0.1. Yes, both
adapters are on the same subnet. It's not documented anywhere that this
should not be the case.

At the time that was written, most people would have one Ethernet
adapter, and one dial-up modem. They just haven't gotten around to a
re-write to cover the contemporary situation. It helps me to think of
the adapter which has the Internet connection as the "Internet
Adapter". The adapter to which the laptop is attached should be
considered the LAN adapter. Now, reading that instruction again, which
is the one that should get IP address 192.168.0.1? The "Internet
Adapter"? Or the "LAN Adapter"?

While you have two network adapters, you really only have one "LAN
Adapter"; the other network adapter is the "Internet Adapter".

You're right, and that way of thinking about it does help. And I
understand the history, but now the docs could be improved...

Finally, the message goes on to tell you to turn on let the other
computers on the network get their addresses automatically. I had
some trouble with this, and finally set the single "other computer[]"
on my network to use the static address 192.168.0.50. What's the
benefit of turning on DHCP for the other computer? Is it just to
make sure that I know to set up the other computer with the same
subnet with the right mask?

The advantage of using DHCP is that you don't have to manually track
which device gets which IP address, how DNS is assigned, and so on. It
really is easier to use DHCP; but you have to be sure that the two
network adapters are in different IP address blocks, or DHCP can make
a squirrelly situation get squirrelier.

I find that addressing two computers manually is triviel; when DHCP is
on, sometimes there's more than one thing in the system trying to give
out IP addresses. It's not a big deal either way.

To begin with, you can't have two different networks with the same
network address.

Yes, I know that.

Your Internet connection is a different network than
your LAN. Your two network adapters in your "host" computer must have
different network addresses. ICS always uses 192.168.0.0/24, assigning
192.168.0.1 to the adapter in the ICS, or "gateway", computer. No
other device connecting to that computer can have that IP address, or
ICS won't work. Because your modem is at IP address 192.168.0.1, you

No, it's not, as I mentioned above. My modem is at 192.168.0.254.

will have a problem getting ICS to work unless you can make some
changes. Since you said that you can change your modem IP address, I
would suggest setting it to 192.168.1.1.

Next, you have to differentiate which network does what. That is where
you think of the network adapters as the "Internet Adapter", and the
"LAN Adapter". Having changed your modem IP address to 192.168.1.1,
your "Internet Adapter" should get an IP address from the modem;
probably 192.168.1.2, but I don't really know. Which modem is it that
you have? BTW, if you couldn't change the IP address on the modem, you
would have to change it to bridge mode, or you could never get ICS to
work.

Now that your "Internet Adapter" is properly configured, you can set
up ICS. When ICS asks which adapter to share, you will check the
"Interenet Adapter". When ICS wants to set the "LAN Adapter" to IP
address 192.168.0.1, there will no longer be a conflict. You can let
ICS handle DHCP, now, and tell the laptop to obtain an IP address
automatically. The last time that I set up ICS, each successive
computer connected to the LAN obtained an IP address one higher than
the last; the laptop would get 192.168.0.2. And so on.

Finally, is your modem truly a router? It can use DHCP to assign IP
addresses? If so, why not invest $10 - $15 for a switch? Instead of
ICS, let the router component of the modem handle IP address
assignment. If the modem can't do that, you should still be able to
use a switch, and just set the IP addresses of the computers manually,
as a static LAN. Then you don't need to run the "host" computer just
to access the Internet.

Well, after all that, and I do appreciate your suggestions...

Why are you so keen on letting my modem/router handle IP address
assignment? There's only one adapter that it's going to see, and like I
said, it's trivial to configure one computer with an address. At work,
where we have 20 computers, I set them all up with DHCP and configured
the Windows server as a DHCP server. (Configuring the Windows DHCP
server service is more work than setting up one computer with a static
IP address, but most routers' DHCP configuration is usually a little
simpler than Windows'.)

The address conflict message that complains that some other device is at
*address* 192.168.0.1, really means that some other device is in the
same *subbnet* as 192.168.0.1; specifically, the LAN adapter that I
should be calling the Internet adapter was in the same subnet. The
message is simply wrong. Telling me that another device in the system
is already using *address* 192.168.0.1 when that is not the case is
simply wrong. A device being on the same subnet is not the same concept
as a device already having that specific *address*. The modem is at
192.168.09.254

----

And the problem was, in fact, the subnets; things actually worked fine
when I changed the subnet of the Internet adapter as you suggested.
Again, I maintain that it's not documented anywhere that the two
adapters should be on different subnets. If I were a networking expert
instead of just a programming expert, then maybe that would be obvious
to me. But with all the documentation out there, someone should at
least mention that issue in passing!

Thanks again.

David Walker

 

[DWalker]

Hi chuck, please see my responses below.

David,

I was replying to your earlier post also, and I was sort of in the
process of figuring it out when you posted the follow-up.

You CAN have the "router to host", and the "host to client", LANs in
the same subnet, but that requires that the ICS host become a bridge.
ICS is a software based NAT router, and routers work best when the
different interfaces are on separate LANs. And, if you want to use
ICS, that means that the "host to client" LAN WILL use 192.168.0/24.
That's one of the "features" (limitations) of ICS.

I agree with you that the message "some other connection on the
network already had the required address 192.168.0.1" is confusing.
Not having seen your network, I can't say for sure, but I'd be almost
willing to bet that both the connection to the router, and the
connection to the client, are creating a bridge. And since ICS
insists on using 192.168.0.1 for its hosts LAN address, it's having
the problem there. If you setup the host as a bridge, you still won't
be able to use 192.168.0.1 anywhere else.

There are so many things about Microsoft Networking that are
confusing. One of the subjects I try to help with is Windows
Networking and Network Neighborhood. If I had a dollar for every time
I've mentioned the Browser as a problem and someone replies "My
Internet connection is fine" or similar, I'd have a lot of dollars.

The "Allow other network users to connect through this computer's
Internet connection" is relative to the host, and the Internet
connection is the network adapter that this computer uses to access
the Internet. In order to share Internet service, you have to have
service. And that's the LAN that should not be on the 192.168.0/24
subnet.

Anyway, if I had a dollar for every time I've thought how confusing
their documentation is, I'd have a hella lot of dollars. But that's
one of the side benefits of the MVP program, I now have a contact in
Microsoft, and I can ask him questions. And I have an avenue for
suggesting documentation improvements (ie KB articles). So instead of
cursing the darkness, I'm now in a position to light a couple candles.
And I've lit a couple so far, and maybe I will get to light some more
during the next few months.

So, to your situation. I strongly recommend that you:
# Change your router LAN to another subnet, say 192.168.1/24.
# Identify the problem with Windows Networking in your laptop LAN, and
restore NBT / TCP/IP as the transport there.

You're right, I changed the router's LAN connection to 192.168.1.1 and the
router itself to 192.168.1.254. Everything worked fine.

As I mentioned to Norman Miller in the other reply, none of the extensive
documentation even mentions in passing that the two adapters should be on a
different subnet. I was thinking they should all be on the same subnet so
they could all talk to each other, but I realise now that without static
routes, the computer can get confused on which adapter to send what data
to.

I'm not a networking expert.

If everything is set up to use DHCP, then that might work also -- but lots
of DSL modem/routers are shipped at address 192.168.0.1 and DHCP on, and I
find it easier to turn off DHCP and manually configure one computer. This
avoids the situations I have seen where more than one device on the network
(usually someone's wireless gateway) is giving out IP addresses at the same
time on the same subnet.

I had previously changed the router to 192.168.0.254 since I knew that ICS
needed 192.168.0.1. Now that I changed it to 192.168.1.254 and set the
computer's "Internet LAN" to 192.168.1.1, everything works great.

Thanks for your help. Maybe someone, somewhere, in all the vast set of
how-tos on ICS, will mention that the subnets need to be different.

And as I also said in the reply to Norman, the message that some other
device in the same system is using *address* 192.168.0.1 really means that
some other device in the system is on the same *subnet*. I'm sure of this,
because you can disable the Internet LAN adapter, and then you're able to
turn on ICS for that adapter without seeing the error message (then you can
re-enable that adapter). That's what I was doing when the host was Windows
2000, and it actually worked (usually).

Being on the same *subnet* is not the same as having the same *address*.
Even I know that! The error message is frustrating. If you can give some
input to the MS people in this repsect for Vista, please do!

Thanks.

David

 

[Chuck]

Hi chuck, please see my responses below.



You're right, I changed the router's LAN connection to 192.168.1.1 and the
router itself to 192.168.1.254. Everything worked fine.

As I mentioned to Norman Miller in the other reply, none of the extensive
documentation even mentions in passing that the two adapters should be on a
different subnet. I was thinking they should all be on the same subnet so
they could all talk to each other, but I realise now that without static
routes, the computer can get confused on which adapter to send what data
to.

I'm not a networking expert.

If everything is set up to use DHCP, then that might work also -- but lots
of DSL modem/routers are shipped at address 192.168.0.1 and DHCP on, and I
find it easier to turn off DHCP and manually configure one computer. This
avoids the situations I have seen where more than one device on the network
(usually someone's wireless gateway) is giving out IP addresses at the same
time on the same subnet.

I had previously changed the router to 192.168.0.254 since I knew that ICS
needed 192.168.0.1. Now that I changed it to 192.168.1.254 and set the
computer's "Internet LAN" to 192.168.1.1, everything works great.

Thanks for your help. Maybe someone, somewhere, in all the vast set of
how-tos on ICS, will mention that the subnets need to be different.

And as I also said in the reply to Norman, the message that some other
device in the same system is using *address* 192.168.0.1 really means that
some other device in the system is on the same *subnet*. I'm sure of this,
because you can disable the Internet LAN adapter, and then you're able to
turn on ICS for that adapter without seeing the error message (then you can
re-enable that adapter). That's what I was doing when the host was Windows
2000, and it actually worked (usually).

Being on the same *subnet* is not the same as having the same *address*.
Even I know that! The error message is frustrating. If you can give some
input to the MS people in this repsect for Vista, please do!

Thanks.

David

Hi David,

There are not really any "experts" in networking here - anybody who truly is an
expert probably is elsewhere. ;-)

Explaining how an ICS server should be configured, with both its Internet
service and its clients connected thru Ethernet, is something you just have to
puzzle thru. As I said before, ICS was originally developed to share dialup
service, where there is no IP connection between the ICS host (a dialup client)
and the dialup modem - just a serial cable. You'll end up with a dialup
"adapter" with an address, but that's its public (WAN) address - not the address
of the ICS server.

I call an ICS server a NAT router, because it has all of the characteristics of
a NAT router:
# It connects two networks.
# It issues ip address settings, thru DHCP, to its clients on the LAN.
# It provides WAN (Internet) service to its clients, using NAT.
# As a router, it works best with one subnet for receiving the Internet service,
and a second for sharing the service. The second, unfortunately, must be
192.168.0/24 - that's not an option.
<http://en.wikipedia.org/wiki/Network_Address_Translation>

Nobody talks about all of these details, because not too many people ask your
questions. I'll probably write something in my spare time, and stick it into my
website. Spare time, right.

Anyway, I'm not sure how this would be addressed in Vista, I have yet to see how
Vista provides ICS, as ICS isn't something that's a heavy feature. It's
basically a kludge, and most folks who need a NAT router buy a NAT router.
That's my extreme recommendation anyway, and one of the few that Winograd and I
agree on. Buy a NAT router, keep the routing off your desktop computer.
<http://nitecruzr.blogspot.com/2005/05/ics-is-ok-but-you-can-do-better.html>

Thanks for your feedback, and the update on your status.

 

[DWalker]

Finally, is your modem truly a router? It can use DHCP to assign IP
addresses? If so, why not invest $10 - $15 for a switch? Instead of
ICS, let the router component of the modem handle IP address
assignment. If the modem can't do that, you should still be able to
use a switch, and just set the IP addresses of the computers manually,
as a static LAN. Then you don't need to run the "host" computer just
to access the Internet.

On thie particular issue, the second computer (the notebook) has a
wireless card, and the "Lan adapter" in my host computer is a PCI
wireless card. They connect peer-to-peer. I can't wire the second
computer to a switch -- I would have to get a wireless base station
instead, which I understand is also fairly cheap these days.

But thanks for the replies; as you saw in my followup to your other
reply, the problem was the different subnets that I had no idea were not
supposed to work -- using the same subnet on the two adapters worked
fine (95% of the time) when the host was Windows 2000.

Thanks.

David Walker