pfSense

networking

Open-source firewall and router software distribution based on FreeBSD, widely deployed as a network security platform.

Pronunciation

Correct

P-F-sense

/piːɛfˈsɛns/

The 'pf' stands for 'packet filter' from BSD — each letter is spoken individually: P-F, then 'sense'. Not pronounced as a single syllable 'pf'.

Source: docs.netgate.com(official docs)