https://csrc.nist.gov/glossary/term/fp_urpf
FP-uRPF - Glossary | CSRC
fpglossarycsrc
https://forums.freebsd.org/threads/pf-firewall-antispoof-rules-vs-urpf.783/
pf firewall - antispoof rules vs. uRPF | The FreeBSD Forums
pf FAQ says that uRPF provides the same functionality as antispoof rules (http://www.openbsd.org/faq/pf/filter.html). Could anyone point out the difference...
pffirewallrulesvsfreebsd