In security parlance, ipfw is a packet-filtering firewall: it checks each packet coming or going through the Macs network interfaces against a set of rules, and allows it to pass or blocks it. Packet-filtering firewalls like ipfw classify network traffic two ways: by type, using port numbers, and by origin and destination, using IP addresses.įor instance, a packet-filtering firewall could accept file-sharing connections from IP addresses of your work network but not from other addresses on the Internet.
To ipfw, Leopard adds a new socket-filter firewall (also known as an application firewall). Rather than using network ports and IP addresses to decide whether to allow a packet, it bases its decision on the application making the network request. When a program asks to accept network traffic, a socket filter checks a list of programs that have been authorized to do so. If the program is on the list, the firewall allows the connection. If the program isnt on the listas in the case of new or upgraded softwareOS X asks you whether to allow the program to accept incoming traffic.
You enable Leopards socket firewall by selecting Set Access For Specific Services And Applications in the Firewall tab of the Security preference pane. When you select that option, youll see a list of allowed and blocked programs.
0 kommentar(er)
