Strange ICS problem

[John]

I have two XP SP2 laptops. Laptop A is connected to the internet through an
ethernet connection with DHCP (I run an Alcatel ADSL modem in DHCP spoofing
mode). The connection works fine.

The two laptops are connected through a 1394 connection. The cable works
fine, file sharing between the computer works perfectly well.
I have shared my internet connection on Laptop A and allowed the 1394
connection to have access to it, Laptop B has recognized that and displays
an Internet Gateway connection in the Network Connections section of the
control panel. So far so good.

As soon as my laptops are connected through firewire, the internet gateway
connection on laptop B seems to be enabled.

The trouble is I usually have to wait for *ages* before having access to the
internet on laptop B. At the beginning I can't seem to be able to ping any
address. Then just DNS queries seem to fail, as I can go on kernel.org for
instance with my browser if I enter the IP address directly. After some time
it suddenly all works but it usually takes a long, long time.

Any idea about what's going on?

It's very frustating because laptop B is my work computer which I have to
connect to a VPN.

Once I get everything running, I don't have any problem during the day.

 

[John]

I think I've cut the problem down to something interesting.
It seems like there is a problem with the DNS. If I access a site for the
first time on laptop B it will never work. I first have a resolve the domain
name into an IP address on laptop A for laptop B to succeed the DNS query,
eg:

1) I try to ping www.bbc.co.uk from laptop B. It doesn't work.
2) I ping the same address from laptop A. It works.
3) I retry from laptop B. Now, it works.

What's going wrong with my configuration?

 

[Steve Winograd [MVP]]

I think I've cut the problem down to something interesting.
It seems like there is a problem with the DNS. If I access a site for the
first time on laptop B it will never work. I first have a resolve the domain
name into an IP address on laptop A for laptop B to succeed the DNS query,
eg:

1) I try to ping www.bbc.co.uk from laptop B. It doesn't work.
2) I ping the same address from laptop A. It works.
3) I retry from laptop B. Now, it works.

What's going wrong with my configuration?

Hmm, ICS via 1394 works fine on my network. Did you change the IP
address (192.168.0.1) that ICS assigned to laptop A's 1394 connection?
That can make ICS act up.

If not, something could be wrong with the DNS relay function on laptop
A. Two possible fixes:

1. Disable and then enable ICS on laptop A, or:

2. Configure laptop B's 1394 connection properties manually:

IP Address: 192.168.0.2
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.0.1
DNS Server = your ISP's DNS server
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional Program
http://mvp.support.microsoft.com

 

[John]

Hmm, ICS via 1394 works fine on my network. Did you change the IP
address (192.168.0.1) that ICS assigned to laptop A's 1394 connection?
That can make ICS act up.

If not, something could be wrong with the DNS relay function on laptop
A. Two possible fixes:

1. Disable and then enable ICS on laptop A, or:

2. Configure laptop B's 1394 connection properties manually:

IP Address: 192.168.0.2
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.0.1
DNS Server = your ISP's DNS server

Thanks for your help Steve, but I have more problems.
I tried what you suggested. It didn't work.

Can we address this issue from the beginning?

First, the 1394 connection status on laptop A says 'Connected' even though
my fireware cable is unplugged from both ends. How the hell is this
possible? No wonder this problem drives me crazy.

Please can somebody help me getting out of this nightmare?

1) I switch off laptop B.
2) I unplug the fireware cable
3) reboot laptop A
4) how on Earth is it possible that Windows report the 1394 connection as
connected?

Steve, please, can we start with this first problem?

 

[John]

Hmm, ICS via 1394 works fine on my network. Did you change the IP
address (192.168.0.1) that ICS assigned to laptop A's 1394 connection?
That can make ICS act up.

If not, something could be wrong with the DNS relay function on laptop
A. Two possible fixes:

1. Disable and then enable ICS on laptop A, or:

2. Configure laptop B's 1394 connection properties manually:

IP Address: 192.168.0.2
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.0.1
DNS Server = your ISP's DNS server

I can no longer see Internet Gateway on laptop B regardless of my
configuration on both laptop A and B now. I have tried everything. I simply
cannot make it again.

 

[John]

Can you explain me the following (let's leave ICS out of the equation for
now):

1) I make sure the cable is unplugged on both ends
2) I configure the 1394 connection on both ends to use DHCP.
3) I disable the 1394 connection on both laptops
4) I reboot both computers

5) Now I plug in the firewire cable (I can hear a beep on both laptops)
6) On both laptops I enable the 1394 connection (I can hear two beeps again)
7) Under the command prompt on laptop B, I have still no IP address
(0.0.0.0)
9) After some time, laptop B IP address is 169.254.111.5. laptop A IP
address is 169.254.96.185.
10) Under Explorer on laptop B, I can connected to my laptop A through
\\LAPTOPA\
and access shared folders after being asked to authenticate.

I am not sure to understand correctly the meaning of the IP addresses
169.254.111.5 and 169.254.96.185. Are they valid - leaving aside ICS for
now - if I simply want to connect two computers through firewire?

 

[Guest]

Those I.P addresses are ones that your network cards default to if they
cannot obtain a I.P address via DHCP (i.e. via Internet Connection Sharing)

TimH

 

[Steve Winograd [MVP]]

Thanks for your help Steve, but I have more problems.
I tried what you suggested. It didn't work.

Can we address this issue from the beginning?

First, the 1394 connection status on laptop A says 'Connected' even though
my fireware cable is unplugged from both ends. How the hell is this
possible? No wonder this problem drives me crazy.

Please can somebody help me getting out of this nightmare?

1) I switch off laptop B.
2) I unplug the fireware cable
3) reboot laptop A
4) how on Earth is it possible that Windows report the 1394 connection as
connected?

Steve, please, can we start with this first problem?

What you're seeing is normal. A 1394 connection reports "Connected"
even when there's no physical connection to another computer. Don't
worry about it.
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional Program
http://mvp.support.microsoft.com

 

[Steve Winograd [MVP]]

Can you explain me the following (let's leave ICS out of the equation for
now):

1) I make sure the cable is unplugged on both ends
2) I configure the 1394 connection on both ends to use DHCP.
3) I disable the 1394 connection on both laptops
4) I reboot both computers

5) Now I plug in the firewire cable (I can hear a beep on both laptops)
6) On both laptops I enable the 1394 connection (I can hear two beeps again)
7) Under the command prompt on laptop B, I have still no IP address
(0.0.0.0)
9) After some time, laptop B IP address is 169.254.111.5. laptop A IP
address is 169.254.96.185.
10) Under Explorer on laptop B, I can connected to my laptop A through
\\LAPTOPA\
and access shared folders after being asked to authenticate.

I am not sure to understand correctly the meaning of the IP addresses
169.254.111.5 and 169.254.96.185. Are they valid - leaving aside ICS for
now - if I simply want to connect two computers through firewire?

What you're seeing is valid and expected when ICS isn't using the1394
connection.

The 1394 connections are configured to obtain an IP address
automatically. Since ICS isn't enabled, they don't have static IP
addresses, and there's no DHCP server to assign them dynamic IP
addresses.

After waiting approximately 1 minute for a DHCP server, XP assigns the
connections compatible 169.254.x.x IP addresses so that the computers
can network with each other. That's called APIPA (Automatic Private
IP Addressing).
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional Program
http://mvp.support.microsoft.com

 

[Steve Winograd [MVP]]

I can no longer see Internet Gateway on laptop B regardless of my
configuration on both laptop A and B now. I have tried everything. I simply
cannot make it again.

I'm sorry, but I don't know what's wrong -- I can't tell from your
reply whether you tried either (or both) of my suggested fixes or
whether you tried something completely different.

On A, right-click the DSL connection, click Properties | Advanced, and
make sure that ICS is enabled. If it asks what connection to use for
the local area network, tell it to use the 1394 connection.

On B, right-click the 1394 connection, click Status | Support |
Details, and check its configuration. What does it show for IP
address, subnet mask, default gateway, and DNS server?
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional Program
http://mvp.support.microsoft.com