I have an XP Pro SP3 laptop, and an XP Home SP3 netbook, both in the same workgroup, and both connected to the same wireless (PC to PC) network (no router involved).
The network is running WEP, as I couldn't get them to connect using WPA or WPA2.
The Windows Firewall is turned off, as Zone Alarm is installed, and Zone Alarm has been configured to allow the newly detected wireless network into the "trusted zone".
I have set the Wireless connections to use manual IP addresses, with subnet masks of 255.255.255.0, and each using the laptop's gateway and DNS addresses, as the laptop is connected to the Internet over USB wireless broadband. The manual IP addresses have been set to 10.1.1.101 & 10.1.1.102.
I can't ping the other PC, on either of the PCs.
Any ideas why?
Best Answer
ZoneAlarm is blocking ICMP traffic. I've seen this problem at many sites that have used this product, and in some cases ZoneAlarm had to be removed completely to get "ping" to work again, followed by either re-installing ZoneAlarm or just using Windows built-in firewall (with Service Pack 3 the Windows firewall is actually pretty good compared to previous versions, which comes pretty close to eliminating third-party firewall software, especially if you have a hardware firewall like a LinkSys router sitting between your computer and the internet to block external attacks).
But before uninstalling ZoneAlarm, check through its configuration options for anything to do with ICMP (the underlying protocol used by "ping" and "traceroute" and other similar tools).
A note about software firewalls: Unfortunately, many software firewalls are a little bit like snake-oil in that they alert the users about all sorts of potential threats for traffic that's just normal, and so users tend to start blocking everything like crazy because they think normal ARP requests are potential attacks. It definitely makes the user feel good about having installed the software firewall, even though this could be a false sense of security.