2nd PC doesn't connect to internet

[news.microsoft.com]

Hi, I've 2 PC Windows XP Pro SP2 connected in LAN (192.168.0.1 and
192.168.0.2). They view and sharing files each other in Windows Explorer
very well.
When I switch on the USB Router (connected to the 1st PC) Windows opens
a "LAN Connection #2" with IP 192.168.0.4 and I can surf the web. This
connection is shared with ICS to the 2nd PC, but from the 2nd PC I can't
surf the web.

Service ALG (Application Level Gateway) is running on the 1st PC.
The Router IP is 192.168.0.3.
From the 2nd PC I can ping 192.168.0.1, but NOT 192.168.0.2, NOT
192.168.0.3 and NOT 192.168.0.4.
TCP-IP properties of 2nd PC is configured so: gateway and DNS is set to
192.168.0.1. I can try to set 192.168.0.3 or 192.168.0.4 but doesn't
work equally.

Besides, if the USB Router is on I can't connect to the 2nd PC from the
1st by Remote Administrator tools.
If I switch off the USB Modem, I instantly can connect to the 2nd from
the 1st.
I always can connect to the 1st PC from the 2nd, even the USB Modem (on
1st PC) in on.
I don't know if all these behaviors are related to the same problem.
What can I do?
Thank you very much

 

[Doug Sherman [MVP]]

This configuration is not working because both adapters in the 1st PC are on
the same subnet - 192.168.0.x. In order to make this work you must change
the router's subnet to something other than 192.168.0.x. Or, you could
disable ICS, set both the first and 2nd PC to obtain an IP automatically,
and bridge the connections on the 1st PC.

Doug Sherman
MCSE, MCSA, MCP+I, MVP

 

[Bill]

Doug Sherman [MVP] ha scritto:

This configuration is not working because both adapters in the 1st PC are on
the same subnet - 192.168.0.x. In order to make this work you must change
the router's subnet to something other than 192.168.0.x. Or, you could
disable ICS, set both the first and 2nd PC to obtain an IP automatically,
and bridge the connections on the 1st PC.

I must keep the same subnet 192.168.0.x to router map port forwarding to
use remote admin tools from home.

If I bridge the connections 192.168.0.4 and 192.168.0.1 on the 1st PC
I've security problem? An intruder can enter in my LAN from the Internet?
Thank you very much

 

[Doug Sherman [MVP]]

Bridging connections where one of them is a public IP poses a security
issue. The 1st PC does not have a public IP, so this issue is not
applicable. I don't understand why you can't reconfigure the router unless
it has extremely limited features. In any event, if you cannot change the
router's subnet, you cannot use ICS. If the router supports static routes,
you could use straight routing instead of bridging.

Doug Sherman
MCSE, MCSA, MCP+I, MVP