Oddity. Cannot ping one way, full access the other way. 1

[Crasty]

I have a network on a internet soho router, (which is not the problem, as I have tried using a simple hub as well.) One computer is running 98SE, the other is running XP home. Both machines are getting their addressing via DHCP, but I've tried to hardcode as well. From the 98 machine, I can access the XP machine, print, get files etc. From the XP machine, I cannot even ping the 98 machine. I can ping the router. I can surf the web and all, I just can't hit that machine. But it's a one way problem. Any ideas?

Thx in advance!

-Crasty

 

[Nettekkie1010]

This is not an answer but an attempt to help you decipher the issue. If the two PC's are on the same subnet the router shouldn't be involved. Download Ethereal and WinPcap from the internet, they're not hard to find. Install them on the both machines, start Ethereal packet capture on your local adapter and issue the PING to the 98 box. Stop the captures and analyze the results. What you're looking for first should resemble the following:

70 32.949656 ARP Who has 172.18.250.2? Tell 172.18.250.150
71 32.952275 ARP 172.18.250.2 is at 00:03:42:c1:90:80
72 32.952281 ICMP Echo (ping) request
73 32.955749 ICMP Echo (ping) reply
75 33.949076 ICMP Echo (ping) request
76 33.952576 ICMP Echo (ping) reply
78 34.950515 ICMP Echo (ping) request
79 34.953998 ICMP Echo (ping) reply
82 35.952123 ICMP Echo (ping) request
83 35.955586 ICMP Echo (ping) reply

From the capture you'll either notice ARP failing (request, no reply) or you'll see ARP succeed and PING fail (echo, no reply; or echo/reply) Either way, from the packet detail you'll be able to quickly pinpoint the source of the problem.

Haveagoodun!
Nettekkie1010

 

[bcastner]

Disable the ICF firewall on the XP machine.

http://support.microsoft.com/?kbid=283673

 

[Crasty]

I'll try the packet capture tonight.. The firewall was my first suspect, but there is no active firewall on either machine at the moment.

 

[bcastner]

If you had previosly installed Norton Internet Security, Zone Alarm or McAfee it is very possible the firewall engine is still running on the machines. Use Task Manager to check, and use MSCONFIG to check again that there is no startup entry.

In addition there are often "hidden" firewalls in antivirus software. PC-Illan, for one, is famous for this. By default it installs a firewall component that will create the results you see.