Setting up a firewall

Just as a building or vehicle uses specially constructed walls to prevent the spread of fire, so computer systems use firewalls to prevent or limit access to certain applications or systems and to protect systems from malicious attacks.

To create a firewall under QNX OS, you can use a combination of:

• IP Filtering to control access to your machine
• Network Address Translation (NAT)—known to Linux users as IP masquerading—to connect several computers through a common external interface

IP Filtering and NAT are handled through the packet filtering (PF) interface with pfctl (see Packet Filtering in the High-Performance Networking Stack User's Guide).