BSD Router Project (BSDRP) is a customized distribution of FreeBSD dedicated to offering IP routing services for small ISPs (not for home use).
Quagga is a routing software suite, providing
implementations of OSPFv2, OSPFv3, RIPv1 and v2, RIPng, IS-IS,
and BGP4+ for Unix platforms, particularly FreeBSD,
Linux, and NetBSD.
A portable source code librarian.
A system-independent interface for user-level packet capture.