Home LAN problem: 1 PC no longer accessible

I have a home LAN. 4 PCs all wired to DSL modem router. 3 x WinXPPro, 1x WinXPHome. TCP/IP address 10.1.1.2 to 10.1.1.5 with router as 10.1.1.1.
All was working find until one of the PCs will nolonger let the other devices talk to it. i.e. 3 of the PCs and router can ping each other but they can't ping the 4th computer. However the 4th computer can ping all the others.

I've tried powering up/down (computers and router), removing firewalls, deinstalling/reinstall file and print sharing, all on the 4th computer but still I can't ping it, even from the router (which I think is weird given it has the DHCP server and is suppling it the IP address.

I'm going nutts. Been working on this for 2 days. Any and all help most welcome.

Regards,
G.O.Varney

 

What is the OS on the problem PC? Is it the XP Home system or one of the XP pros?

 

The problem PC is running XP Pro SP2.

 

Can you do a tracert to the IP?
Just type "tracert xxx.xxx.xxx.xxx" in a CMD window
Traffic might be routed wrong, but honestly it sounds lika a firewall issue

 

Tracing route to 10.1.1.4 over a maximum of 30 hops

1 * * * Request timed out.
2 * * * Request timed out.
3 * * * Request timed out.
4 * * * Request timed out.
5 * * * Request timed out.
6 * * * Request timed out.
7 * * * Request timed out.
8 * * * Request timed out.
9 * * * Request timed out.
10 * * * Request timed out.
11 * * * Request timed out.
12 * * * Request timed out.
13 * * * Request timed out.
14 * * * Request timed out.
15 * * * Request timed out.
16 * * * Request timed out.
17 * * * Request timed out.
18 * * * Request timed out.
19 * * * Request timed out.
20 * * * Request timed out.
21 * * * Request timed out.
22 * * * Request timed out.
23 * * * Request timed out.
24 * * * Request timed out.
25 * * * Request timed out.
26 * * * Request timed out.
27 * * * Request timed out.
28 * * * Request timed out.
29 * * * Request timed out.
30 * * * Request timed out.

Trace complete.

 

And you are sure that windows firewall is not enabled? Because ICMP(ping\tracert etc..) is blocked by default. Since you can ping from it, but not to it, its most likely a firewall. If routing was worng, neither would work.
You could also try a network sniffer to see where the package is going. I know there is a free one out there, but cant remember the name. Can anyone help here?

 

I agree it must be a firewall problem but I can definately say that the firewall is off, both Windows and CIF.

I have been reading that CIF and the Windows firewall can still operate even though they are OFF.

So I have decided to de-installed CIF.

And now with no CIF I can ping OK. Very happy.

So I think I'll give CIF a miss and get an alternate Firewall.

Thanks for your help. I'll let you and the BBS know the result once I have the new Firewall installed.

G.O.Varney

 

try network magic to set it up.

www.networkmagic.com

 

Installed Symantec Client Firewall. V8.7.4.97

Problem Gone.

Happy Chappy Now.

Thanks for your help.
G.O.Varney