在局域網中，希望從其他機器通過IP訪問webserver.如果webserver 是xp系統，訪問者也是xp系統，直接就可以訪問了，但是有些系統是win7.這個時候80端口是被防火牆給阻止了，所以要在防火牆上重新設置規則，方法如下：
To add a rule in the Windows Firewall for port 80, do the following:
Go to the Control Panel and launch "Windows Firewall"
Go to "Advanced Settings"
Select "Inbound Rules" in the left pane
Select "New Rule" in the right pane
In the New Inbound Rule Wizard, select "Port" as Rule Type, then click on "Next"
Select "TCP and put "80" (and any other ports you want to open) in "Specific local ports", then click on "Next"
Select "Allow the connection", then click on "Next"
Select the network location where the rule should apply (select them all if you're not sure), then click on "Next"
Give a name and an optional description
That should do it.
