Provided by: horst_5.0-2_amd64 
NAME
horst - Highly Optimized Radio Scanning Tool
SYNOPSIS
horst [-v] [-h] [-q] [-D] [-a] [-c file] [-C channel] [-i interface] [-t sec] [-V view] [-d ms] [-b
bytes] [-M file] [-s] [-u] [-N] [-n IP] [-p port] [-o file] [-X name] [-x command] [-e mac] [-f pkt_name]
[-m mode] [-B BSSID]
DESCRIPTION
horst is a small, lightweight IEEE802.11 wireless LAN analyzer with a text interface. Its basic function
is similar to tcpdump, Wireshark or Kismet, but it's much smaller and shows different, aggregated
information which is not easily available from other tools. It is mainly targeted at debugging wireless
LANs with a focus on ad-hoc (IBSS) mode in larger mesh networks. It can be useful to get a quick overview
of what's going on on all wireless LAN channels and to identify problems.
• Shows signal values per station.
• Calculates channel utilization ("usage") by adding up the amount of time the packets actually occupy
the medium.
• "Spectrum Analyzer" shows signal levels and usage per channel.
• Text-based "graphical" packet history, with signal, packet type and physical rate
• Shows all stations per ESSID and the live TSF per node as it is counting.
• Detects IBSS "splits" (same ESSID but different BSSID - this is a common driver problem).
• Statistics of packets/bytes per physical rate and per packet type.
• Has some support for mesh protocols (OLSR and batman).
• Can filter specific packet types, source MAC addresses or BSSIDs.
• Client/server support for monitoring on remote nodes.
• Can be controlled via a named pipe.
See MONITOR MODE below for more information about the network interface setup.
OPTIONS
-v Show version.
-h Show summary of options.
-q Quiet mode. Don't show user interface. This is only useful in conjunction when running in server
mode (-C) or writing to a file (-o).
-D Show lot's of debugging output, including a full package dump. Only available when compiled with
DEBUG=1.
-a Always add virtual monitor interface. Don't try to set existing interface to monitor mode.
-c configfile
Use configfile instead of the default "/etc/horst.conf".
-C channel
Set inital channel (number not frequency).
-i intf
Operate on the given network interface instead of the default "wlan0".
-t sec Timeout (remove) nodes after not receiving packets from them for this time in seconds (default: 60
sec).
-V view
Display 'view'. Valid view names are "history", "hist", "essid", "statistics", "stats",
"spectrum", "spec".
-d ms Display update interval. The default value of 100ms can be increased to reduce CPU load caused by
redrawing the screen.
-b bytes
Receive buffer size. The receive buffer size can be set to tune memory consumption and reduce lost
packets under load.
-M filename
MAC address to host name mapping file. The file can either be a dhcp.leases file from dnsmasq or
contain mappings in the form "MAC<space>name" (e.g.: "00:01:02:03:04:05 test") line by line
(default filename: /tmp/dhcp.leases).
-s Show a poor mans "spectrum analyzer". The same can be achieved by running horst as normal and
pressing the button 's' (Spec); then 'c' (Chan) and 'a' (Automatically change channel).
-u Upper channel limit for the automatic channel change.
-N Allow client connections. Server mode. Only one client connection is supported at the moment
(default: off).
-n IP Connect to a horst instance running in server-mode at the specified IP address.
-p port
Use the specified port (default: 4444) for client/server connections.
-o filename
Write a information about each received packet into file. Note that you can send to STDOUT by
using -o /dev/stdout. See OUTPUT FILE FORMAT below.
-X Accept control commands on a named pipe (default /tmp/horst).
-X name
Accept control commands on a named pipe with given name or set pipe name used with -x.
-x command
Send control command to another horst process who was started with -X and then exit. Multiple
commands can be concatenated with ';'. Currently implemented commands are:
pause
Pause horst processing
resume
Resume horst processing
reset
Reset all history, statistics and views
channel=X
Set channel channel number
channel_scan=X
Automatically change channels (1 or 0)
channel_dwell=X
Set channel dwell time when automatically changing channel (ms)
channel_upper=X
Set max channel when automatically changing channel
outfile=X
Write to outfile named X. If the file is already open, it is cleared and re-openend. If
filename is not specified ("outfile=") any existing file is closed and no file is written.
-e MAC Filter all MAC addresses except these, to show only packets originating from the specified MAC
addresses. This option can be specified multiple times.
-f pkt_type
Filter all packets except these. This option can be specified multiple times. For valid packet
names see NAMES AND ABBREVIATIONS below.
-m (AP|STA|ADH|PRB|WDS|UNKNOWN)
Only show/include packets and nodes of this mode. Note that the mode is infered by the information
of packets we received and it may take some time until a node is properly classified. This option
can be specified multiple times.
-B BSSID
Only show/include packets which belong to the given BSSID.
TEXT USER INTERFACE
The ncurses-based text interface tries to display a lot of information, so it may look confusing at
first. Below we describe the different screens and options.
Main screen
The initial (main) screen is split into three parts. The upper area shows a list of aggregated
"node" information, the most useful information about each sender which was discovered, one per
line:
/
"Spinner" to show activity
Pk
Percentage of this node's packets in relation to all received packets
Re%
Percentage of retried frames of all frames this node sent
Cha
Channel number
Sig
Signal value (RSSI) in dBm
RAT
Physical data rate
TRANSMITTER
MAC address of sender
MODE
Operating Mode (AP, AHD, PRB, STA, WDS), see "NAMES AND ABBREVIATIONS"
ENCR
Encryption (WPA1, WPA2, WEP)
ESSID
ESSID
INFO
Additional info like "BATMAN", IP address...
The lower area shows a scrolling list of packets as they come in:
Cha
Channel number
Sig
Signal value (RSSI) in dBm
RAT
Physical data rate
TRANSMITTER
MAC address of sender
BSSID
BSSID
TYPE
Packet type, see "NAMES AND ABBREVIATIONS"
INFO
Additional info like ESSID, TFS, IP address...
The lower right box shows bar graphs for:
Signal of last received packet in green
bps Bits per second of all received packets
Usage Percentage of channel use
The lower edge is the menu and status bar, it shows which keys to press for other screens. The
status shows ">" when horst is running or "=" when it is paused, then "F" when any kind of filter
is active, the Channel, the monitor interface in use and the time.
Pause ('p' or <space>)
Can be used to pause/resume horst. When horst is paused it will loose packets received in the mean
time.
Reset ('r')
Clears all history and aggregated statistical data.
History ('h')
The history screen scrolls from right to left and shows a bar for each packet indicating the
signal level. In the line below that, the packet type is indicated by one character (See NAMES AND
ABBREVIATIONS below) and the rough physical data rate is indicated below that in blue.
ESSID ('e')
The ESSID screen groups information by ESSID and shows the mode (AP, IBSS), the MAC address of the
sender, the BSSID, the TSF, the beacon interval, the channel, the signal, a "W" when encrytoion is
used and the IP address if known.
Statistics ('a')
The statistics screen groups packets by physical rate and by packet type and shows other kinds of
aggregated and statistical information based on packets.
Spectrum Analyzer ('s')
The "poor mans spectrum analyzer" screen is only really useful when horst is started with the -s
option or the "Automatically change channel" option is selected in the "Chan" settings, or the
config option channel_scan is set.
It shows the available channels horizontally and vertical bars for each channel:
Signal in green
Physical rate in blue
Channel usage in orange/brown
By pressing the 'n' key, the display can be changed to show only the average signal level on each channel
and the last 4 digits of the MAC address of the individual nodes at the level (height) they were
received. This can give a quick graphical overview of the distance of nodes.
Filters ('f')
This configuration dialog can be used to define the active filters.
Channel Settings ('c')
This configuration dialog can be used to change the channel changing behaviour of horst or to
change to a different channel manually.
Sort ('o')
Only active in the main screen, can be used to sort the node list in the upper area by Signal,
Time, BSSID or Channel.
NAMES AND ABBREVIATIONS
802.11 standard frames
Management frames
──┬────────┬────────────────────────
a │ ASOCRQ │ Association request
A │ ASOCRP │ Associaion response
a │ REASRQ │ Reassociation request
A │ REASRP │ Reassociation response
p │ PROBRQ │ Probe request
P │ PROBRP │ Probe response
T │ TIMING │ Timing Advertisement
B │ BEACON │ Beacon
t │ ATIM │ ATIM
D │ DISASC │ Disassociation
u │ AUTH │ Authentication
U │ DEAUTH │ Deauthentication
C │ ACTION │ Action
c │ ACTNOA │ Action No Ack
Control frames
──┬────────┬───────────────────
w │ CTWRAP │ Control Wrapper
b │ BACKRQ │ Block Ack Request
B │ BACK │ Block Ack
s │ PSPOLL │ PS-Poll
R │ RTS │ RTS
C │ CTS │ CTS
K │ ACK │ ACK
f │ CFEND │ CF-End
f │ CFENDK │ CF-End + CF-Ack
Data frames
──┬────────┬────────────────────────────────
D │ DATA │ Data
F │ DCFACK │ Data + CF-Ack
F │ DCFPLL │ Data + CF-Poll
F │ DCFKPL │ Data + CF-Ack + CF-Poll
n │ NULL │ Null (no data)
f │ CFACK │ CF-Ack (no data)
f │ CFPOLL │ CF-Poll (no data)
f │ CFCKPL │ CF-Ack + CF-Poll (no data)
Q │ QDATA │ QoS Data
F │ QDCFCK │ QoS Data + CF-Ack
F │ QDCFPL │ QoS Data + CF-Poll
F │ QDCFKP │ QoS Data + CF-Ack + CF-Poll
N │ QDNULL │ QoS Null (no data)
f │ QCFPLL │ QoS CF-Poll (no data)
f │ QCFKPL │ QoS CF-Ack + CF-Poll (no data)
* │ BADFCS │ Bad frame checksum
Packet types
Similar to 802.11 frames above but higher level and as a bit field (types can overlap, e.g. DATA +
IP) and including more information, like IP, ARP, BATMAN, OLSR...
Packet types
───────┬──────────┬────────────────────────────────────────────
CTRL │ 0x000001 │ WLAN Control frame
MGMT │ 0x000002 │ WLAN Management frame
DATA │ 0x000004 │ WLAN Data frame
BADFCS │ 0x000008 │ WLAN frame checksum (FCS) bad
BEACON │ 0x000010 │ WLAN beacon frame
PROBE │ 0x000020 │ WLAN probe request or response
ASSOC │ 0x000040 │ WLAN associaction request/response frame
AUTH │ 0x000080 │ WLAN authentication frame
RTSCTS │ 0x000100 │ WLAN RTS or CTS
ACK │ 0x000200 │ WLAN ACK or BlockACK
NULL │ 0x000400 │ WLAN NULL Data frame
QDATA │ 0x000800 │ WLAN QoS Data frame (WME/WMM)
ARP │ 0x001000 │ ARP packet
IP │ 0x002000 │ IP packet
ICMP │ 0x004000 │ IP ICMP packet
UDP │ 0x008000 │ IP UDP
TCP │ 0x010000 │ IP TCP
OLSR │ 0x020000 │ OLSR protocol
BATMAN │ 0x040000 │ BATMAND Layer3 or BATMAN-ADV Layer 2 frame
MESHZ │ 0x080000 │ MeshCruzer protocol
Operating modes
Bit field of operating mode type which is infered from received packets. Modes may overlap, i.e.
it is common to see STA and PRB at the same time.
Operating modes
────────┬──────┬─────────────────────────────
AP │ 0x01 │ Access Point (AP)
ADH │ 0x02 │ Ad-hoc node
STA │ 0x04 │ Station (AP client)
PRB │ 0x08 │ Sent PROBE requests
WDS │ 0x10 │ WDS or 4 Address frames
UNKNOWN │ 0x20 │ Unknown e.g. RTS/CTS or ACK
MONITOR MODE
To capture and analyze 802.11 traffic, the interface needs to be in monitor mode. You can either setup
the interface manually beforehand or let horst setup it automatically at startup. Usually, root
privileges are required to modify an interface setup.
horst should work with any wireleass LAN card and driver which supports monitor mode, with either
"prism2" or "radiotap" headers. This includes most modern mac80211-based drivers.
If the interface is not in monitor mode at startup, horst first tries to put the interface in monitor
mode. If it fails (for example when the interface is already in use), a new virtual monitor interface
(horst0) is added and used instead. The virtual monitor interface is removed when horst exits. Note that
changing the channel via a virtual monitor interface is not allowed by the wireless driver, so options -C
and -s do not work when virtual monitor interface is used.
Examples of how to setup an interface manually:
Using iw:
iw wlan0 interface add mon0 type monitor
or
sudo iw wlan1 set type monitor
sudo iw wlan1 set channel 6
Using iwconfig:
iwconfig wlan0 mode monitor
iwconfig wlan0 channel 1
ifconfig wlan0 up
Using madwifi:
wlanconfig wlan0 create wlandev wifi0 wlanmode monitor
Using hostap:
iwconfig wlan0 mode monitor
iwpriv wlan0 monitor_type 1
NOTES
Signal values and ranges may differ between wireless drivers and versions.
OUTPUT FILE FORMAT
The format of the output file (-o flag) is a comma separated list of the following fields in the
following order, one packet each line.
timestamp
Local time, including microseconds (e.g. 2015-05-16 15:05:44.338806 +0300)
packet_type
802.11 MAC packet type name as defined in the section "NAMES AND ABBREVIATIONS".
wlan_src
Source MAC address
wlan_dst
Destination MAC address
wlan_bssid
BSSID
pkt_types
Higher level packet name as defined in section "NAMES AND ABBREVIATIONS".
phy_signal
Signal strength in dBm
wlan_len
Packet length (MAC)
phy_rate
Physical data rate
phy_freq
Received while tuned to this frequency.
wlan_tsf
TFS timer value
wlan_essid
ESSID, network name
wlan_mode
Operating modes as defined in "NAMES AND ABBREVIATIONS".
wlan_channel
Channel number
wlan_wep
Encryption in use
wlan_wpa
WPA1 Encryption in use
wlan_rsn
RSN (WPA2) Encryption in use
ip_src IP source address (if available)
ip_dst IP destionation address (if available)
SEE ALSO
horst.conf(5), tcpdump(1), wireshark(1), kismet(1), README, http://br1.einfach.org/tech/horst
AUTHOR
horst was written by Bruno Randolf <br1@einfach.org>.
This manual page was written by Antoine Beaupré <anarcat@debian.org>, for the Debian project (and may be
used by others).
July 22, 2015 HORST(8)