MORE ANTIVIURS  PF PACKET  FILTER What is OpenBSD-Firewall? OpenBSD-Firewall (PF packet filter) is a BSD licensed stateful packet filter, a central piece of software firewalls. And common firewall can be defined as dedicated device, or software running on another computer, which inspects network traffic passing through it, and denies or permits passage based on a set of rules, but specifically, firewall protection is a method of hosts and networks connected to other hosts and networks against attacks (defined as attacks attempts to gain unauthorized access to our network, disruption of services listening or alter the communications , theft of data or software, corruption of data or software) from the outside and from within.