ipnat(5) on FreeBSD
The text 50d2421c5219, as FreeBSD 5.2.1-RELEASE, FreeBSD 5.2-RELEASE, FreeBSD 5.1-RELEASE, FreeBSD 4.10-RELEASE, FreeBSD 4.9-RELEASE, FreeBSD 4.8-RELEASE shipped it.
IP NAT file format
The text 50d2421c5219, as FreeBSD 5.2.1-RELEASE, FreeBSD 5.2-RELEASE, FreeBSD 5.1-RELEASE, FreeBSD 4.10-RELEASE, FreeBSD 4.9-RELEASE, FreeBSD 4.8-RELEASE shipped it.
IP NAT file format