ARP-FINGERPRINT(1) General Commands Manual ARP-FINGERPRINT(1)
NAME
arp-fingerprint - Fingerprint a system using ARP
SYNOPSIS
arp-fingerprint [options2] target
The target should be specified as a single IP address or hostname. You
cannot specify multiple targets, IP networks or ranges.
If you use an IP address for the target, you can use the -o option to
pass the --numeric option to arp-scan, which will prevent it from
attempting DNS lookups. This can speed up the fingerprinting process,
especially on systems with a slow or faulty DNS configuration.
DESCRIPTION
arp-fingerprint fingerprints the specified target host using the ARP
protocol.
It sends various different types of ARP request to the target, and
records which types it responds to. From this, it constructs a finger-
print string consisting of "1" where the target responded and "0" where
it did not. An example of a fingerprint string is 010001000002. This
fingerprint string is then used to lookup the likely target operating
system.
Many of the fingerprint strings are shared by several operating sys-
tems, so there is not always a one-to-one mapping between fingerprint
strings and operating systems. Also the fact that a system's finger-
print matches a certain operating system (or list of operating systems)
does not necessarily mean that the system being fingerprinted is that
operating system, although it is quite likely. This is because the list
of operating systems is not exhaustive; it is just what I have discov-
ered to date, and there are bound to be operating systems that are not
listed.
The ARP fingerprint of a system is generally a function of that sys-
tem's kernel (although it is possible for the ARP function to be imple-
mented in user space, it almost never is).
Sometimes, an operating system can give different fingerprints depend-
ing on the configuration. An example is Linux, which will respond to a
non-local source IP address if that IP is routed through the interface
being tested. This is both good and bad: on one hand it makes the fin-
gerprinting task more complex; but on the other, it can allow some
aspects of the system configuration to be determined.
Sometimes the fact that two different operating systems share a common
ARP fingerprint string points to a re-use of networking code. One exam-
ple of this is Windows NT and FreeBSD.
arp-fingerprint uses arp-scan to send the ARP requests and receive the
replies.
There are other methods that can be used to fingerprint a system using
arp-scan which can be used in addition to arp-fingerprint. These addi-
tional methods are not included in arp-fingerprint either because they
are likely to cause disruption to the target system, or because they
require knowledge of the target's configuration that may not always be
available.
arp-fingerprint is still being developed, and the results should not be
relied on. As most of the ARP requests that it sends are non-standard,
it is possible that it may disrupt some systems, so caution is advised.
If you find a system that arp-fingerprint reports as UNKNOWN, and you
know what operating system it is running, could you please send details
of the operating system and fingerprint to arp-scan@nta-monitor.com so
I can include it in future versions. Please include the exact version
of the operating system if you know it, as fingerprints sometimes
change between versions.
OPTIONS
-h Display a brief usage message and exit.
-v Display verbose progress messages.
-o <option-string>
Pass specified options to arp-scan. You need to enclose the
options string in quotes if it contains spaces. e.g. -o "-I
eth1". The commonly used options are --interface (-I) and
--numeric (-N).
EXAMPLES
$ arp-fingerprint 192.168.0.1
192.168.0.1 01000100000 Linux 2.2, 2.4, 2.6
$ arp-fingerprint -o "-N -I eth1" 192.168.0.202
192.168.0.202 11110100000 FreeBSD 5.3, Win98, WinME, NT4, 2000, XP, 2003
NOTES
arp-fingerprint is implemented in Perl, so you need to have the Perl
interpreter installed on your system to use it.
AUTHOR
Roy Hills <Roy.Hills@nta-monitor.com>
SEE ALSO
arp-scan(1)
http://www.nta-monitor.com/wiki/2 The arp-scan wiki page.
April 5, 2007 ARP-FINGERPRINT(1)