.TH NFNL_OSF 8 "" "iptables 1.8.4" "iptables 1.8.4"

.SH NAME
nfnl_osf \- OS fingerprint loader utility
.SH SYNOPSIS

.ad l
.in +8
.ti -8
.B nfnl_osf
.BI -f " fingerprints"
[
.B -d
]

.SH DESCRIPTION
The
.B nfnl_osf
utility allows to load a set of operating system signatures into the kernel for
later matching against using iptables'
.B osf
match.

.SH OPTIONS

.TP
.BI -f " fingerprints"
Read signatures from file
.IR fingerprints .

.TP
.B -d
Instead of adding the signatures from
.I fingerprints
into the kernel, remove them.

.SH EXIT STATUS
Exit status is 0 if command succeeded, otherwise a negative return code
indicates the type of error which happened:

.TP
.B -1
Illegal arguments passed, fingerprints file not readable or failure in netlink
communication.

.TP
.B -ENOENT
Fingerprints file not specified.

.TP
.B -EINVAL
Netlink handle initialization failed or fingerprints file format invalid.

.SH FILES

An up to date set of operating system signatures can be downloaded from
http://www.openbsd.org/cgi-bin/cvsweb/src/etc/pf.os .

.SH SEE ALSO

The description of
.B osf
match in
.BR iptables-extensions (8)
contains further information about the topic as well as example
.B nfnl_osf
invocations.