NAME¶
nping - Network packet generation tool / ping utility
SYNOPSIS¶
nping [Options] {targets}
DESCRIPTION¶
Nping is an open-source tool for network packet generation,
response analysis and response time measurement. Nping allows users to
generate network packets of a wide range of protocols, letting them tune
virtually any field of the protocol headers. While Nping can be used as a
simple ping utility to detect active hosts, it can also be used as a raw
packet generator for network stack stress tests, ARP poisoning, Denial of
Service attacks, route tracing, and other purposes.
Additionally, Nping offers a special mode of operation called the
"Echo Mode", that lets users see how the generated probes change
in transit, revealing the differences between the transmitted packets and
the packets received at the other end. See section "Echo Mode" for
details.
The output from Nping is a list of the packets that are being sent
and received. The level of detail depends on the options used.
A typical Nping execution is shown in Example 1. The only
Nping arguments used in this example are -c, to specify the number of
times to target each host, --tcp to specify TCP Probe Mode, -p
80,433 to specify the target ports; and then the two target
hostnames.
Example 1. A representative Nping
execution
# nping -c 1 --tcp -p 80,433 scanme.nmap.org google.com
Starting Nping ( https://nmap.org/nping )
SENT (0.0120s) TCP 96.16.226.135:50091 > 64.13.134.52:80 S ttl=64 id=52072 iplen=40 seq=1077657388 win=1480
RCVD (0.1810s) TCP 64.13.134.52:80 > 96.16.226.135:50091 SA ttl=53 id=0 iplen=44 seq=4158134847 win=5840 <mss 1460>
SENT (1.0140s) TCP 96.16.226.135:50091 > 74.125.45.100:80 S ttl=64 id=13932 iplen=40 seq=1077657388 win=1480
RCVD (1.1370s) TCP 74.125.45.100:80 > 96.16.226.135:50091 SA ttl=52 id=52913 iplen=44 seq=2650443864 win=5720 <mss 1430>
SENT (2.0140s) TCP 96.16.226.135:50091 > 64.13.134.52:433 S ttl=64 id=8373 iplen=40 seq=1077657388 win=1480
SENT (3.0140s) TCP 96.16.226.135:50091 > 74.125.45.100:433 S ttl=64 id=23624 iplen=40 seq=1077657388 win=1480
Statistics for host scanme.nmap.org (64.13.134.52):
| Probes Sent: 2 | Rcvd: 1 | Lost: 1 (50.00%)
|_ Max rtt: 169.720ms | Min rtt: 169.720ms | Avg rtt: 169.720ms
Statistics for host google.com (74.125.45.100):
| Probes Sent: 2 | Rcvd: 1 | Lost: 1 (50.00%)
|_ Max rtt: 122.686ms | Min rtt: 122.686ms | Avg rtt: 122.686ms
Raw packets sent: 4 (160B) | Rcvd: 2 (92B) | Lost: 2 (50.00%)
Tx time: 3.00296s | Tx bytes/s: 53.28 | Tx pkts/s: 1.33
Rx time: 3.00296s | Rx bytes/s: 30.64 | Rx pkts/s: 0.67
Nping done: 2 IP addresses pinged in 4.01 seconds
The newest version of Nping can be obtained with Nmap at
https://nmap.org. The newest version of this man page is available at
https://nmap.org/book/nping-man.html.
-->
.SH "OPTIONS SUMMARY"
This options summary is printed when Nping is run with no
arguments. It helps people remember the most common options, but is no
substitute for the in-depth documentation in the rest of this manual. Some
obscure options aren't even included here.
Nping 0.7.92SVN ( https://nmap.org/nping )
Usage: nping [Probe mode] [Options] {target specification}
TARGET SPECIFICATION:
Targets may be specified as hostnames, IP addresses, networks, etc.
Ex: scanme.nmap.org, microsoft.com/24, 192.168.0.1; 10.0.*.1-24
PROBE MODES:
--tcp-connect : Unprivileged TCP connect probe mode.
--tcp : TCP probe mode.
--udp : UDP probe mode.
--icmp : ICMP probe mode.
--arp : ARP/RARP probe mode.
--tr, --traceroute : Traceroute mode (can only be used with
TCP/UDP/ICMP modes).
TCP CONNECT MODE:
-p, --dest-port <port spec> : Set destination port(s).
-g, --source-port <portnumber> : Try to use a custom source port.
TCP PROBE MODE:
-g, --source-port <portnumber> : Set source port.
-p, --dest-port <port spec> : Set destination port(s).
--seq <seqnumber> : Set sequence number.
--flags <flag list> : Set TCP flags (ACK,PSH,RST,SYN,FIN...)
--ack <acknumber> : Set ACK number.
--win <size> : Set window size.
--badsum : Use a random invalid checksum.
UDP PROBE MODE:
-g, --source-port <portnumber> : Set source port.
-p, --dest-port <port spec> : Set destination port(s).
--badsum : Use a random invalid checksum.
ICMP PROBE MODE:
--icmp-type <type> : ICMP type.
--icmp-code <code> : ICMP code.
--icmp-id <id> : Set identifier.
--icmp-seq <n> : Set sequence number.
--icmp-redirect-addr <addr> : Set redirect address.
--icmp-param-pointer <pnt> : Set parameter problem pointer.
--icmp-advert-lifetime <time> : Set router advertisement lifetime.
--icmp-advert-entry <IP,pref> : Add router advertisement entry.
--icmp-orig-time <timestamp> : Set originate timestamp.
--icmp-recv-time <timestamp> : Set receive timestamp.
--icmp-trans-time <timestamp> : Set transmit timestamp.
ARP/RARP PROBE MODE:
--arp-type <type> : Type: ARP, ARP-reply, RARP, RARP-reply.
--arp-sender-mac <mac> : Set sender MAC address.
--arp-sender-ip <addr> : Set sender IP address.
--arp-target-mac <mac> : Set target MAC address.
--arp-target-ip <addr> : Set target IP address.
IPv4 OPTIONS:
-S, --source-ip : Set source IP address.
--dest-ip <addr> : Set destination IP address (used as an
alternative to {target specification} ).
--tos <tos> : Set type of service field (8bits).
--id <id> : Set identification field (16 bits).
--df : Set Don't Fragment flag.
--mf : Set More Fragments flag.
--evil : Set Reserved / Evil flag.
--ttl <hops> : Set time to live [0-255].
--badsum-ip : Use a random invalid checksum.
--ip-options <S|R [route]|L [route]|T|U ...> : Set IP options
--ip-options <hex string> : Set IP options
--mtu <size> : Set MTU. Packets get fragmented if MTU is
small enough.
IPv6 OPTIONS:
-6, --IPv6 : Use IP version 6.
--dest-ip : Set destination IP address (used as an
alternative to {target specification}).
--hop-limit : Set hop limit (same as IPv4 TTL).
--traffic-class <class> : : Set traffic class.
--flow <label> : Set flow label.
ETHERNET OPTIONS:
--dest-mac <mac> : Set destination mac address. (Disables
ARP resolution)
--source-mac <mac> : Set source MAC address.
--ether-type <type> : Set EtherType value.
PAYLOAD OPTIONS:
--data <hex string> : Include a custom payload.
--data-string <text> : Include a custom ASCII text.
--data-length <len> : Include len random bytes as payload.
ECHO CLIENT/SERVER:
--echo-client <passphrase> : Run Nping in client mode.
--echo-server <passphrase> : Run Nping in server mode.
--echo-port <port> : Use custom <port> to listen or connect.
--no-crypto : Disable encryption and authentication.
--once : Stop the server after one connection.
--safe-payloads : Erase application data in echoed packets.
TIMING AND PERFORMANCE:
Options which take <time> are in seconds, or append 'ms' (milliseconds),
's' (seconds), 'm' (minutes), or 'h' (hours) to the value (e.g. 30m, 0.25h).
--delay <time> : Adjust delay between probes.
--rate <rate> : Send num packets per second.
MISC:
-h, --help : Display help information.
-V, --version : Display current version number.
-c, --count <n> : Stop after <n> rounds.
-e, --interface <name> : Use supplied network interface.
-H, --hide-sent : Do not display sent packets.
-N, --no-capture : Do not try to capture replies.
--privileged : Assume user is fully privileged.
--unprivileged : Assume user lacks raw socket privileges.
--send-eth : Send packets at the raw Ethernet layer.
--send-ip : Send packets using raw IP sockets.
--bpf-filter <filter spec> : Specify custom BPF filter.
OUTPUT:
-v : Increment verbosity level by one.
-v[level] : Set verbosity level. E.g: -v4
-d : Increment debugging level by one.
-d[level] : Set debugging level. E.g: -d3
-q : Decrease verbosity level by one.
-q[N] : Decrease verbosity level N times
--quiet : Set verbosity and debug level to minimum.
--debug : Set verbosity and debug to the max level.
EXAMPLES:
nping scanme.nmap.org
nping --tcp -p 80 --flags rst --ttl 2 192.168.1.1
nping --icmp --icmp-type time --delay 500ms 192.168.254.254
nping --echo-server "public" -e wlan0 -vvv
nping --echo-client "public" echo.nmap.org --tcp -p1-1024 --flags ack
SEE THE MAN PAGE FOR MANY MORE OPTIONS, DESCRIPTIONS, AND EXAMPLES
TARGET SPECIFICATION¶
Everything on the Nping command line that isn't an option or an
option argument is treated as a target host specification. Nping uses the
same syntax for target specifications that Nmap does. The simplest case is a
single target given by IP address or hostname.
Nping supports CIDR-style addressing. You can append
/numbits to an IPv4 address or hostname and Nping will send probes to
every IP address for which the first numbits are the same as for the
reference IP or hostname given. For example, 192.168.10.0/24 would send
probes to the 256 hosts between 192.168.10.0 (binary: 11000000 10101000
00001010 00000000) and 192.168.10.255 (binary: 11000000 10101000 00001010
11111111), inclusive. 192.168.10.40/24 would ping exactly the same targets.
Given that the host scanme.nmap.org is at the IP address 64.13.134.52, the
specification scanme.nmap.org/16 would send probes to the 65,536 IP
addresses between 64.13.0.0 and 64.13.255.255. The smallest allowed value is
/0, which targets the whole Internet. The largest value is /32, which
targets just the named host or IP address because all address bits are
fixed.
CIDR notation is short but not always flexible enough. For
example, you might want to send probes to 192.168.0.0/16 but skip any IPs
ending with .0 or .255 because they may be used as subnet network and
broadcast addresses. Nping supports this through octet range addressing.
Rather than specify a normal IP address, you can specify a comma-separated
list of numbers or ranges for each octet. For example, 192.168.0-255.1-254
will skip all addresses in the range that end in .0 or .255, and
192.168.3-5,7.1 will target the four addresses 192.168.3.1, 192.168.4.1,
192.168.5.1, and 192.168.7.1. Either side of a range may be omitted; the
default values are 0 on the left and 255 on the right. Using - by itself is
the same as 0-255, but remember to use 0- in the first octet so the target
specification doesn't look like a command-line option. Ranges need not be
limited to the final octets: the specifier 0-.-.13.37 will send probes to
all IP addresses on the Internet ending in .13.37. This sort of broad
sampling can be useful for Internet surveys and research.
IPv6 addresses can only be specified by their fully qualified IPv6
address or hostname. CIDR and octet ranges aren't supported for IPv6 because
they are rarely useful.
Nping accepts multiple host specifications on the command line,
and they don't need to be the same type. The command nping
scanme.nmap.org 192.168.0.0/8 10.0.0,1,3-7.- does what you would
expect.
OPTION SPECIFICATION¶
Nping is designed to be very flexible and fit a wide variety of
needs. As with most command-line tools, its behavior can be adjusted using
command-line options. These general principles apply to option arguments,
unless stated otherwise.
Options that take integer numbers can accept values specified in
decimal, octal or hexadecimal base. When a number starts with 0x, it will be
treated as hexadecimal; when it simply starts with 0, it will be treated as
octal. Otherwise, Nping will assume the number has been specified in base
10. Virtually all numbers that can be supplied from the command line are
unsigned so, as a general rule, the minimum value is zero. Users may also
specify the word random or rand to make Nping generate a random value within
the expected range.
IP addresses may be given as IPv4 addresses (e.g. 192.168.1.1),
IPv6 addresses (e.g. 2001:db8:85a3::8e4c:760:7146), or hostnames, which will
be resolved using the default DNS server configured in the host system.
Options that take MAC addresses accept the usual colon-separated 6
hex byte format (e.g. 00:50:56:d4:01:98). Hyphens may also be used instead
of colons (e.g. 00-50-56-c0-00-08). The special word random or rand sets a
random address and the word broadcast or bcast sets ff:ff:ff:ff:ff:ff.
GENERAL OPERATION¶
Unlike other ping and packet generation tools, Nping supports
multiple target host and port specifications. While this provides great
flexibility, it is not obvious how Nping handles situations where there is
more than one host and/or more than one port to send probes to. This section
explains how Nping behaves in these cases.
When multiple target hosts are specified, Nping rotates among them
in round-robin fashion. This gives slow hosts more time to send their
responses before another probe is sent to them. Ports are also scheduled
using round robin. So, unless only one port is specified, Nping never sends
two probes to the same target host and port consecutively.
The loop around targets is the “inner loop” and the
loop around ports is the “outer loop”. All targets will be
sent a probe for a given port before moving on to the next port. Between
probes, Nping waits a configurable amount of time called the
“inter-probe delay”, which is controlled by the --delay
option. These examples show how it works.
# nping --tcp -c 2 1.1.1.1 -p 100-102
Starting Nping ( https://nmap.org/nping )
SENT (0.0210s) TCP 192.168.1.77 > 1.1.1.1:100
SENT (1.0230s) TCP 192.168.1.77 > 1.1.1.1:101
SENT (2.0250s) TCP 192.168.1.77 > 1.1.1.1:102
SENT (3.0280s) TCP 192.168.1.77 > 1.1.1.1:100
SENT (4.0300s) TCP 192.168.1.77 > 1.1.1.1:101
SENT (5.0320s) TCP 192.168.1.77 > 1.1.1.1:102
# nping --tcp -c 2 1.1.1.1 2.2.2.2 3.3.3.3 -p 8080
Starting Nping ( https://nmap.org/nping )
SENT (0.0230s) TCP 192.168.0.21 > 1.1.1.1:8080
SENT (1.0240s) TCP 192.168.0.21 > 2.2.2.2:8080
SENT (2.0260s) TCP 192.168.0.21 > 3.3.3.3:8080
SENT (3.0270s) TCP 192.168.0.21 > 1.1.1.1:8080
SENT (4.0290s) TCP 192.168.0.21 > 2.2.2.2:8080
SENT (5.0310s) TCP 192.168.0.21 > 3.3.3.3:8080
# nping --tcp -c 1 --delay 500ms 1.1.1.1 2.2.2.2 3.3.3.3 -p 137-139
Starting Nping ( https://nmap.org/nping )
SENT (0.0230s) TCP 192.168.0.21 > 1.1.1.1:137
SENT (0.5250s) TCP 192.168.0.21 > 2.2.2.2:137
SENT (1.0250s) TCP 192.168.0.21 > 3.3.3.3:137
SENT (1.5280s) TCP 192.168.0.21 > 1.1.1.1:138
SENT (2.0280s) TCP 192.168.0.21 > 2.2.2.2:138
SENT (2.5310s) TCP 192.168.0.21 > 3.3.3.3:138
SENT (3.0300s) TCP 192.168.0.21 > 1.1.1.1:139
SENT (3.5330s) TCP 192.168.0.21 > 2.2.2.2:139
SENT (4.0330s) TCP 192.168.0.21 > 3.3.3.3:139
PROBE MODES¶
Nping supports a wide variety of protocols. Although in some cases
Nping can automatically determine the mode from the options used, it is
generally a good idea to specify it explicitly.
--tcp-connect (TCP Connect mode)
TCP connect mode is the default mode when a user does not
have raw packet privileges. Instead of writing raw packets as most other modes
do, Nping asks the underlying operating system to establish a connection with
the target machine and port by issuing the connect system call. This is the
same high-level system call that web browsers, P2P clients, and most other
network-enabled applications use to establish a connection. It is part of a
programming interface known as the Berkeley Sockets API. Rather than read raw
packet responses off the wire, Nping uses this API to obtain status
information on each connection attempt. For this reason, you will not be able
to see the contents of the packets that are sent or received but only status
information about the TCP connection establishment taking place.
--tcp (TCP mode)
TCP is the mode that lets users create and send any kind
of TCP packet. TCP packets are sent embedded in IP packets that can also be
tuned. This mode can be used for many different purposes. For example you
could try to discover open ports by sending TCP SYN messages without
completing the three-way handshake. This technique is often referred to as
half-open scanning, because you don't open a full TCP connection. You send a
SYN packet, as if you are going to open a real connection and then wait for a
response. A SYN/ACK indicates the port is open, while a RST indicates it's
closed. If no response is received one could assume that some intermediate
network device is filtering the responses. Another use could be to see how a
remote TCP/IP stack behaves when it receives a non-RFC-compliant packet, like
one with both SYN and RST flags set. One could also do some evil by creating
custom RST packets using an spoofed IP address with the intent of closing an
active TCP connection.
--udp (UDP mode)
UDP mode can have two different behaviours. Under normal
circumstances, it lets users create custom IP/UDP packets. However, if Nping
is run by a user without raw packet privileges and no changes to the default
protocol headers are requested, then Nping enters the unprivileged UDP mode
which basically sends UDP packets to the specified target hosts and ports
using the sendto system call. Note that in this unprivileged mode it is not
possible to see low-level header information of the packets on the wire but
only status information about the amount of bytes that are being transmitted
and received. UDP mode can be used to interact with any UDP-based server.
Examples are DNS servers, streaming servers, online gaming servers, and port
knocking/single-packet authorization daemons.
--icmp (ICMP mode)
ICMP mode is the default mode when the user runs Nping
with raw packet privileges. Any kind of ICMP message can be created. The
default ICMP type is Echo, i.e., ping. ICMP mode can be used for many
different purposes, from a simple request for a timestamp or a netmask to the
transmission of fake destination unreachable messages, custom redirects, and
router advertisements.
--arp (ARP/RARP mode)
ARP lets you create and send a few different ARP-related
packets. These include ARP, RARP, DRARP, and InARP requests and replies. This
mode can ban be used to perform low-level host discovery, and conduct
ARP-cache poisoning attacks.
--traceroute (Traceroute mode)
Traceroute is not a mode by itself but a complement to
TCP, UDP, and ICMP modes. When this option is specified Nping will set the IP
TTL value of the first probe to 1. When the next router receives the packet it
will drop it due to the expiration of the TTL and it will generate an ICMP
destination unreachable message. The next probe will have a TTL of 2 so now
the first router will forward the packet while the second router will be the
one that drops the packet and generates the ICMP message. The third probe will
have a TTL value of 3 and so on. By examining the source addresses of all
those ICMP Destination Unreachable messages it is possible to determine the
path that the probes take until they reach their final destination.
TCP CONNECT MODE¶
-p port_spec, --dest-port
port_spec (Target ports)
This option specifies which ports you want to try to
connect to. It can be a single port, a comma-separated list of ports (e.g.
80,443,8080), a range (e.g. 1-1023), and any combination of those (e.g.
21-25,80,443,1024-2048). The beginning and/or end values of a range may be
omitted, causing Nping to use 1 and 65535, respectively. So you can specify
-p- to target ports from 1 through 65535. Using port zero is allowed if you
specify it explicitly.
-g portnumber, --source-port
portnumber (Spoof source port)
This option asks Nping to use the specified port as
source port for the TCP connections. Note that this might not work on all
systems or may require root privileges. Specified value must be an integer in
the range [0–65535].
TCP MODE¶
-p port_spec, --dest-port
port_spec (Target ports)
This option specifies which destination ports you want to
send probes to. It can be a single port, a comma-separated list of ports (e.g.
80,443,8080), a range (e.g. 1-1023), and any combination of those (e.g.
21-25,80,443,1024-2048). The beginning and/or end values of a range may be
omitted, causing Nping to use 1 and 65535, respectively. So you can specify
-p- to target ports from 1 through 65535. Using port zero is allowed if you
specify it explicitly.
-g portnumber, --source-port
portnumber (Spoof source port)
This option asks Nping to use the specified port as
source port for the TCP connections. Note that this might not work on all
systems or may require root privileges. Specified value must be an integer in
the range [0–65535].
--seq seqnumber (Sequence Number)
Specifies the TCP sequence number. In SYN packets this is
the initial sequence number (ISN). In a normal transmission this corresponds
to the sequence number of the first byte of data in the segment.
seqnumber must be a number in the range [0–4294967295].
--flags flags (TCP Flags)
This option specifies which flags should be set in the
TCP packet.
flags may be specified in three different ways:
1.As a comma-separated list of flags, e.g. --flags
syn,ack,rst
2.As a list of one-character flag initials, e.g.
--flags SAR tells Nping to set flags SYN, ACK, and RST.
3.As an 8-bit hexadecimal number, where the supplied
number is the exact value that will be placed in the flags field of the TCP
header. The number should start with the prefix 0x and should be in the range
[0x00–0xFF], e.g. --flags 0x20 sets the URG flag as 0x20 corresponds to
binary 00100000 and the URG flag is represented by the third bit.
There are 8 possible flags to set: CWR, ECN, URG, ACK, PSH, RST,
SYN, and FIN. The special value ALL means to set all flags. NONE means to
set no flags. It is important that if you don't want any flag to be set, you
request it explicitly because in some cases the SYN flag may be set by
default. Here is a brief description of the meaning of each flag:
CWR (Congestion Window Reduced)
Set by an ECN-Capable sender when it reduces its
congestion window (due to a retransmit timeout, a fast retransmit or in
response to an ECN notification.
ECN (Explicit Congestion Notification)
During the three-way handshake it indicates that sender
is capable of performing explicit congestion notification. Normally it means
that a packet with the IP Congestion Experienced flag set was received during
normal transmission. See RFC 3168 for more information.
URG (Urgent)
Segment is urgent and the urgent pointer field carries
valid information.
ACK (Acknowledgement)
The segment carries an acknowledgement and the value of
the acknowledgement number field is valid and contains the next sequence
number that is expected from the receiver.
PSH (Push)
The data in this segment should be immediately pushed to
the application layer on arrival.
RST (Reset)
There was some problem and the sender wants to abort the
connection.
SYN (Synchronize)
The segment is a request to synchronize sequence numbers
and establish a connection. The sequence number field contains the sender's
initial sequence number.
FIN (Finish)
The sender wants to close the connection.
--win size (Window Size)
Specifies the TCP window size, this is, the number of
octets the sender of the segment is willing to accept from the receiver at one
time. This is usually the size of the reception buffer that the OS allocates
for a given connection. size must be a number in the range
[0–65535].
--badsum (Invalid Checksum)
Asks Nping to use an invalid TCP checksum for the packets
sent to target hosts. Since virtually all host IP stacks properly drop these
packets, any responses received are likely coming from a firewall or an IDS
that didn't bother to verify the checksum. For more details on this technique,
see
https://nmap.org/p60-12.html.
UDP MODE¶
-p port_spec, --dest-port
port_spec (Target ports)
This option specifies which ports you want UDP datagrams
to be sent to. It can be a single port, a comma-separated list of ports (e.g.
80,443,8080), a range (e.g. 1-1023), and any combination of those (e.g.
21-25,80,443,1024-2048). The beginning and/or end values of a range may be
omitted, causing Nping to use 1 and 65535, respectively. So you can specify
-p- to target ports from 1 through 65535. Using port zero is allowed if you
specify it explicitly.
-g portnumber, --source-port
portnumber (Spoof source port)
This option asks Nping to use the specified port as
source port for the transmitted datagrams. Note that this might not work on
all systems or may require root privileges. Specified value must be an integer
in the range [0–65535].
--badsum (Invalid Checksum)
Asks Nping to use an invalid UDP checksum for the packets
sent to target hosts. Since virtually all host IP stacks properly drop these
packets, any responses received are likely coming from a firewall or an IDS
that didn't bother to verify the checksum. For more details on this technique,
see
https://nmap.org/p60-12.html.
ICMP MODE¶
--icmp-type type (ICMP type)
This option specifies which type of ICMP messages should
be generated. type can be supplied in two different ways. You can use
the official type numbers assigned by IANA[1] (e.g. --icmp-type
8 for ICMP Echo Request), or you can use any of the mnemonics listed in
the section called “ICMP Types”.
--icmp-code code (ICMP code)
This option specifies which ICMP code should be included
in the generated ICMP messages. code can be supplied in two different
ways. You can use the official code numbers assigned by IANA[1] (e.g.
--icmp-code 1 for Fragment Reassembly Time Exceeded), or you can use
any of the mnemonics listed in the section called “ICMP
Codes”.
--icmp-id id (ICMP identifier)
This option specifies the value of the identifier used in
some of the ICMP messages. In general it is used to match request and reply
messages. id must be a number in the range [0–65535].
--icmp-seq seq (ICMP sequence)
This option specifies the value of the sequence number
field used in some ICMP messages. In general it is used to match request and
reply messages. id must be a number in the range
[0–65535].
--icmp-redirect-addr addr (ICMP Redirect
address)
This option sets the address field in ICMP Redirect
messages. In other words, it sets the IP address of the router that should be
used when sending IP datagrams to the original destination. addr can be
either an IPv4 address or a hostname.
--icmp-param-pointer pointer (ICMP Parameter
Problem pointer)
This option specifies the pointer that indicates the
location of the problem in ICMP Parameter Problem messages. pointer
should be a number in the range [0–255]. Normally this option is only
used when ICMP code is set to 0 ("Pointer indicates the
error").
--icmp-advert-lifetime ttl (ICMP Router
Advertisement Lifetime)
This option specifies the router advertisement lifetime,
this is, the number of seconds the information carried in an ICMP Router
Advertisement can be considered valid for. ttl must be a positive
integer in the range [0–65535].
--icmp-advert-entry
addr,pref (ICMP Router Advertisement
Entry)
This option adds a Router Advertisement entry to an ICMP
Router Advertisement message. The parameter must be two values separated by a
comma. addr is the router's IP and can be specified either as an IP
address in dot-decimal notation or as a hostname. pref is the
preference level for the specified IP. It must be a number in the range
[0–4294967295]. An example is --icmp-advert-entry
192.168.128.1,3.
--icmp-orig-time timestamp (ICMP Originate
Timestamp)
This option sets the Originate Timestamp in ICMP
Timestamp messages. The Originate Timestamp is expressed as the number of
milliseconds since midnight UTC and it corresponds to the time the sender last
touched the Timestamp message before its transmission. timestamp can be
specified as a regular time (e.g. 10s, 3h, 1000ms), or the special string now.
You can add or subtract values from now, for example --icmp-orig-time
now-2s, --icmp-orig-time now+1h, --icmp-orig-time
now+200ms.
--icmp-recv-time timestamp (ICMP Receive
Timestamp)
This option sets the Receive Timestamp in ICMP Timestamp
messages. The Receive Timestamp is expressed as the number of milliseconds
since midnight UTC and it corresponds to the time the echoer first touched the
Timestamp message on receipt. timestamp is as with
--icmp-orig-time.
--icmp-trans-time timestamp (ICMP Transmit
Timestamp)
This option sets the Transmit Timestamp in ICMP Timestamp
messages. The Transmit Timestamp is expressed as the number of milliseconds
since midnight UTC and it corresponds to the time the echoer last touched the
Timestamp message before its transmission. timestamp is as with
--icmp-orig-time.
ICMP Types¶
These identifiers may be used as mnemonics for the ICMP type
numbers given to the --icmp-type option. In general there are three
forms of each identifier: the full name (e.g. destination-unreachable), the
short name (e.g. dest-unr), or the initials (e.g. du). In ICMP types that
request something, the word "request" is omitted.
echo-reply, echo-rep, er
Echo Reply (type 0). This message is sent in response to
an Echo Request message.
destination-unreachable, dest-unr, du
Destination Unreachable (type 3). This message indicates
that a datagram could not be delivered to its destination.
source-quench, sour-que, sq
Source Quench (type 4). This message is used by a
congested IP device to tell other device that is sending packets too fast and
that it should slow down.
redirect, redi, r
Redirect (type 5). This message is normally used by
routers to inform a host that there is a better route to use for sending
datagrams. See also the --icmp-redirect-addr option.
echo-request, echo, e
Echo Request (type 8). This message is used to test the
connectivity of another device on a network.
router-advertisement, rout-adv, ra
Router Advertisement (type 9). This message is used by
routers to let hosts know of their existence and capabilities. See also the
--icmp-advert-lifetime option.
router-solicitation, rout-sol, rs
Router Solicitation (type 10). This message is used by
hosts to request Router Advertisement messages from any listening
routers.
time-exceeded, time-exc, te
Time Exceeded (type 11). This message is generated by
some intermediate device (normally a router) to indicate that a datagram has
been discarded before reaching its destination because the IP TTL
expired.
parameter-problem, member-pro, pp
Parameter Problem (type 12). This message is used when a
device finds a problem with a parameter in an IP header and it cannot continue
processing it. See also the --icmp-param-pointer option.
timestamp, time, tm
Timestamp Request (type 13). This message is used to
request a device to send a timestamp value for propagation time calculation
and clock synchronization. See also the --icmp-orig-time,
--icmp-recv-time, and --icmp-trans-time.
timestamp-reply, time-rep, tr
Timestamp Reply (type 14). This message is sent in
response to a Timestamp Request message.
information, info, i
Information Request (type 15). This message is now
obsolete but it was originally used to request configuration information from
another device.
information-reply, info-rep, ir
Information Reply (type 16). This message is now obsolete
but it was originally sent in response to an Information Request message to
provide configuration information.
mask-request, mask, m
Address Mask Request (type 17). This message is used to
ask a device to send its subnet mask.
mask-reply, mask-rep, mr
Address Mask Reply (type 18). This message contains a
subnet mask and is sent in response to a Address Mask Request message.
traceroute, trace, tc
Traceroute (type 30). This message is normally sent by an
intermediate device when it receives an IP datagram with a traceroute option.
ICMP Traceroute messages are still experimental, see RFC 1393 for more
information.
ICMP Codes¶
These identifiers may be used as mnemonics for the ICMP code
numbers given to the --icmp-code option. They are listed by the ICMP
type they correspond to.
Destination Unreachable
network-unreachable, netw-unr, net
Code 0. Datagram could not be delivered to its
destination network (probably due to some routing problem).
host-unreachable, host-unr, host
Code 1. Datagram was delivered to the destination network
but it was impossible to reach the specified host (probably due to some
routing problem).
protocol-unreachable, prot-unr, proto
Code 2. The protocol specified in the Protocol field of
the IP datagram is not supported by the host to which the datagram was
delivered.
port-unreachable, port-unr, port
Code 3. The TCP/UDP destination port was invalid.
needs-fragmentation, need-fra, frag
Code 4. Datagram had the DF bit set but it was too large
for the MTU of the next physical network so it had to be dropped.
source-route-failed, sour-rou, routefail
Code 5. IP datagram had a Source Route option but a
router couldn't pass it to the next hop.
network-unknown, netw-unk, net?
Code 6. Destination network is unknown. This code is
never used. Instead, Network Unreachable is used.
host-unknown, host-unk, host?
Code 7. Specified host is unknown. Usually generated by a
router local to the destination host to inform of a bad address.
host-isolated, host-iso, isolated
Code 8. Source Host Isolated. Not used.
network-prohibited, netw-pro, !net
Code 9. Communication with destination network is
administratively prohibited (source device is not allowed to send packets to
the destination network).
host-prohibited, host-pro, !host
Code 10. Communication with destination host is
administratively prohibited. (The source device is allowed to send packets to
the destination network but not to the destination device.)
network-tos, unreachable-network-tos, netw-tos, tosnet
Code 11. Destination network unreachable because it
cannot provide the type of service specified in the IP TOS field.
host-tos, unreachable-host-tos, toshost
Code 12. Destination host unreachable because it cannot
provide the type of service specified in the IP TOS field.
communication-prohibited, comm-pro, !comm
Code 13. Datagram could not be forwarded due to filtering
that blocks the message based on its contents.
host-precedence-violation, precedence-violation, prec-vio,
violation
Code 14. Precedence value in the IP TOS field is not
permitted.
precedence-cutoff, prec-cut, cutoff
Code 15. Precedence value in the IP TOS field is lower
than the minimum allowed for the network.
Redirect
redirect-network, redi-net, net
Code 0. Redirect all future datagrams with the same
destination network as the original datagram, to the router specified in the
Address field. The use of this code is prohibited by RFC 1812.
redirect-host, redi-host, host
Code 1. Redirect all future datagrams with the same
destination host as the original datagram, to the router specified in the
Address field.
redirect-network-tos, redi-ntos, redir-ntos
Code 2. Redirect all future datagrams with the same
destination network and IP TOS value as the original datagram, to the router
specified in the Address field. The use of this code is prohibited by RFC
1812.
redirect-host-tos, redi-htos, redir-htos
Code 3. Redirect all future datagrams with the same
destination host and IP TOS value as the original datagram, to the router
specified in the Address field.
Router Advertisement
normal-advertisement, norm-adv, normal, zero, default, def
Code 0. Normal router advertisement. In Mobile IP:
Mobility agent can act as a router for IP datagrams not related to mobile
nodes.
not-route-common-traffic, not-rou, mobile-ip, !route,
!commontraffic
Code 16. Used for Mobile IP. The mobility agent does not
route common traffic. All foreign agents must forward to a default router any
datagrams received from a registered mobile node
Time Exceeded
ttl-exceeded-in-transit, ttl-exc, ttl-transit
Code 0. IP Time To Live expired during transit.
fragment-reassembly-time-exceeded, frag-exc, frag-time
Code 1. Fragment reassembly time has been exceeded.
Parameter Problem
pointer-indicates-error, poin-ind, pointer
Code 0. The pointer field indicates the location of the
problem. See the --icmp-param-pointer option.
missing-required-option, miss-option, option-missing
Code 1. IP datagram was expected to have an option that
is not present.
bad-length, bad-len, badlen
Code 2. The length of the IP datagram is incorrect.
ARP MODE¶
--arp-type type (ICMP Type)
This option specifies which type of ARP messages should
be generated. type can be supplied in two different ways. You can use
the official numbers assigned by IANA[2] (e.g. --arp-type 1 for
ARP Request), or you can use one of the mnemonics from the section called
“ARP Types”.
--arp-sender-mac mac (Sender MAC address)
This option sets the Sender Hardware Address field of the
ARP header. Although ARP supports many types of link layer addresses,
currently Nping only supports MAC addresses. mac must be specified
using the traditional MAC notation (e.g. 00:0a:8a:32:f4:ae). You can also use
hyphens as separators (e.g. 00-0a-8a-32-f4-ae).
--arp-sender-ip addr (Sender IP address)
This option sets the Sender IP field of the ARP header.
addr can be given as an IPv4 address or a hostname.
--arp-target-mac mac (target MAC address)
This option sets the Target Hardware Address field of the
ARP header.
--arp-target-ip addr (target ip address)
This option sets the Target IP field of the ARP
header.
ARP Types¶
These identifiers may be used as mnemonics for the ARP type
numbers given to the --arp-type option.
arp-request, arp, a
ARP Request (type 1). ARP requests are used to translate
network layer addresses (normally IP addresses) to link layer addresses
(usually MAC addresses). Basically, and ARP request is a broadcasted message
that asks the host in the same network segment that has a given IP address to
provide its MAC address.
arp-reply, arp-rep, ar
ARP Reply (type 2). An ARP reply is a message that a host
sends in response to an ARP request to provide its link layer address.
rarp-request, rarp, r
RARP Requests (type 3). RARP requests are used to
translate a link layer address (normally a MAC address) to a network layer
address (usually an IP address). Basically a RARP request is a broadcasted
message sent by a host that wants to know his own IP address because it
doesn't have any. It was the first protocol designed to solve the
bootstrapping problem. However, RARP is now obsolete and DHCP is used instead.
For more information about RARP see RFC 903.
rarp-reply, rarp-rep, rr
RARP Reply (type 4). A RARP reply is a message sent in
response to a RARP request to provide an IP address to the host that sent the
RARP request in the first place.
drarp-request, drarp, d
Dynamic RARP Request (type 5). Dynamic RARP is an
extension to RARP used to obtain or assign a network layer address from a
fixed link layer address. DRARP was used mainly in Sun Microsystems platforms
in the late 90's but now it's no longer used. See RFC 1931 for more
information.
drarp-reply, drarp-rep, dr
Dynamic RARP Reply (type 6). A DRARP reply is a message
sent in response to a RARP request to provide network layer address.
drarp-error, drarp-err, de
DRARP Error (type 7). DRARP Error messages are usually
sent in response to DRARP requests to inform of some error. In DRARP Error
messages, the Target Protocol Address field is used to carry an error code
(usually in the first byte). The error code is intended to tell why no target
protocol address is being returned. For more information see RFC 1931.
inarp-request, inarp, i
Inverse ARP Request (type 8). InARP requests are used to
translate a link layer address to a network layer address. It is similar to
RARP request but in this case, the sender of the InARP request wants to know
the network layer address of another node, not its own address. InARP is
mainly used in Frame Relay and ATM networks. For more information see RFC
2390.
inarp-reply, inarp-rep, ir
Inverse ARP Reply (type 9). InARP reply messages are sent
in response to InARP requests to provide the network layer address associated
with the host that has a given link layer address.
arp-nak, an
ARP NAK (type 10). ARP NAK messages are an extension to
the ATMARP protocol and they are used to improve the robustness of the ATMARP
server mechanism. With ARP NAK, a client can determine the difference between
a catastrophic server failure and an ATMARP table lookup failure. See RFC 1577
for more information.
IPV4 OPTIONS¶
-S addr, --source-ip
addr (Source IP Address)
Sets the source IP address. This option lets you specify
a custom IP address to be used as source IP address in sent packets. This
allows spoofing the sender of the packets. addr can be an IPv4 address
or a hostname.
--dest-ip addr (Destination IP Address)
Adds a target to Nping's target list. This option is
provided for consistency but its use is deprecated in favor of plain target
specifications. See the section called “TARGET
SPECIFICATION”.
--tos tos (Type of Service)
Sets the IP TOS field. The TOS field is used to carry
information to provide quality of service features. It is normally used to
support a technique called Differentiated Services. See RFC 2474 for more
information. tos must be a number in the range [0–255].
--id id (Identification)
Sets the IPv4 Identification field. The Identification
field is a 16-bit value that is common to all fragments belonging to a
particular message. The value is used by the receiver to reassemble the
original message from the fragments received. id must be a number in
the range [0–65535].
--df (Don't Fragment)
Sets the Don't Fragment bit in sent packets. When an IP
datagram has its DF flag set, intermediate devices are not allowed to fragment
it so if it needs to travel across a network with a MTU smaller that datagram
length the datagram will have to be dropped. Normally an ICMP Destination
Unreachable message is generated and sent back to the sender.
--mf (More Fragments)
Sets the More Fragments bit in sent packets. The MF flag
is set to indicate the receiver that the current datagram is a fragment of
some larger datagram. When set to zero it indicates that the current datagram
is either the last fragment in the set or that it is the only fragment.
--evil (Reserved / Evil)
Sets the Reserved / Evil bit in sent packets. The Evil
flag helps firewalls and other network security systems to distinguish between
datagrams that have malicious intent and those that are merely unusual. When
set, it indicates that the datagram has evil intent, instructing insecure
systems to succumb. Setting it to zero indicates no evil intent. The option is
implied if environmental variable SCRIPT_KIDDIE is set to a non-zero
value.
--ttl hops (Time To Live)
Sets the IPv4 Time-To-Live (TTL) field in sent packets to
the given value. The TTL field specifies how long the datagram is allowed to
exist on the network. It was originally intended to represent a number of
seconds but it actually represents the number of hops a packet can traverse
before being dropped. The TTL tries to avoid a situation in which
undeliverable datagrams keep being forwarded from one router to another
endlessly. hops must be a number in the range [0–255].
--badsum-ip (Invalid IP checksum)
Asks Nping to use an invalid IP checksum for packets sent
to target hosts. Note that some systems (like most Linux kernels), may fix the
checksum before placing the packet on the wire, so even if Nping shows the
incorrect checksum in its output, the packets may be transparently corrected
by the kernel.
--ip-options S|R [route]|L [route]|T|U ...,
--ip-options hex string (IP Options)
The IP protocol offers several options which may be
placed in packet headers. Unlike the ubiquitous TCP options, IP options are
rarely seen due to practicality and security concerns. In fact, many Internet
routers block the most dangerous options such as source routing. Yet options
can still be useful in some cases for determining and manipulating the network
route to target machines. For example, you may be able to use the record route
option to determine a path to a target even when more traditional
traceroute-style approaches fail. Or if your packets are being dropped by a
certain firewall, you may be able to specify a different route with the strict
or loose source routing options.
The most powerful way to specify IP options is to simply pass in
hexadecimal data as the argument to --ip-options. Precede each hex
byte value with \x. You may repeat certain characters by following them with
an asterisk and then the number of times you wish them to repeat. For
example, \x01\x07\x04\x00*4 is the same as \x01\x07\x04\x00\x00\x00\x00.
Note that if you specify a number of bytes that is not a multiple
of four, an incorrect IP header length will be set in the IP packet. The
reason for this is that the IP header length field can only express
multiples of four. In those cases, the length is computed by dividing the
header length by 4 and rounding down. This will affect the way the header
that follows the IP header is interpreted, showing bogus information in
Nping or in the output of any sniffer. Although this kind of situation might
be useful for some stack stress tests, users would normally want to specify
explicit padding, so the correct header length is set.
Nping also offers a shortcut mechanism for specifying options.
Simply pass the letter R, T, or U to request record-route, record-timestamp,
or both options together, respectively. Loose or strict source routing may
be specified with an L or S followed by a space and then a space-separated
list of IP addresses.
For more information and examples of using IP options with Nping,
see the mailing list post at
https://seclists.org/nmap-dev/2006/q3/0052.html.
--mtu size (Maximum Transmission Unit)
This option sets a fictional MTU in Nping so IP datagrams
larger than size are fragmented before transmission. size must
be specified in bytes and corresponds to the number of octets that can be
carried on a single link-layer frame.
IPV6 OPTIONS¶
-6, --ipv6 (Use IPv6)
Tells Nping to use IP version 6 instead of the default
IPv4. It is generally a good idea to specify this option as early as possible
in the command line so Nping can parse it soon and know in advance that the
rest of the parameters refer to IPv6. The command syntax is the same as usual
except that you also add the
-6 option. Of course, you must use IPv6
syntax if you specify an address rather than a hostname. An address might look
like
3ffe:7501:4819:2000:210:f3ff:fe03:14d0, so hostnames are
recommended.
While IPv6 hasn't exactly taken the world by storm, it gets
significant use in some (usually Asian) countries and most modern operating
systems support it. To use Nping with IPv6, both the source and target of
your packets must be configured for IPv6. If your ISP (like most of them)
does not allocate IPv6 addresses to you, free tunnel brokers are widely
available and work fine with Nping. You can use the free IPv6 tunnel broker
service at http://www.tunnelbroker.net.
Please note that IPv6 support is still highly experimental and
many modes and options may not work with it.
-S addr, --source-ip
addr (Source IP Address)
Sets the source IP address. This option lets you specify
a custom IP address to be used as source IP address in sent packets. This
allows spoofing the sender of the packets. addr can be an IPv6 address
or a hostname.
--dest-ip addr (Destination IP Address)
Adds a target to Nping's target list. This option is
provided for consistency but its use is deprecated in favor of plain target
specifications. See the section called “TARGET
SPECIFICATION”.
--flow label (Flow Label)
Sets the IPv6 Flow Label. The Flow Label field is 20 bits
long and is intended to provide certain quality-of-service properties for
real-time datagram delivery. However, it has not been widely adopted, and not
all routers or endpoints support it. Check RFC 2460 for more information.
label must be an integer in the range [0–1048575].
--traffic-class class (Traffic Class)
Sets the IPv6 Traffic Class. This field is similar to the
TOS field in IPv4, and is intended to provide the Differentiated Services
method, enabling scalable service discrimination in the Internet without the
need for per-flow state and signaling at every hop. Check RFC 2474 for more
information. class must be an integer in the range
[0–255].
--hop-limit hops (Hop Limit)
Sets the IPv6 Hop Limit field in sent packets to the given value.
The Hop Limit field specifies how long the datagram is allowed to exist on
the network. It represents the number of hops a packet can traverse before
being dropped. As with the TTL in IPv4, IPv6 Hop Limit tries to avoid a
situation in which undeliverable datagrams keep being forwarded from one
router to another endlessly. hops must be a number in the range
[0–255].
ETHERNET OPTIONS¶
In most cases Nping sends packets at the raw IP level. This means
that Nping creates its own IP packets and transmits them through a raw
socket. However, in some cases it may be necessary to send packets at the
raw Ethernet level. This happens, for example, when Nping is run under
Windows (as Microsoft has disabled raw socket support since Windows XP SP2),
or when Nping is asked to send ARP packets. Since in some cases it is
necessary to construct ethernet frames, Nping offers some options to
manipulate the different fields.
--dest-mac mac (Ethernet Destination MAC
Address)
This option sets the destination MAC address that should
be set in outgoing Ethernet frames. This is useful in case Nping can't
determine the next hop's MAC address or when you want to route probes through
a router other than the configured default gateway. The MAC address should
have the usual format of six colon-separated bytes, e.g. 00:50:56:d4:01:98.
Alternatively, hyphens may be used instead of colons. Use the word random or
rand to generate a random address, and broadcast or bcast to use
ff:ff:ff:ff:ff:ff. If you set up a bogus destination MAC address your probes
may not reach the intended targets.
--source-mac mac (Ethernet Source MAC
Address)
This option sets the source MAC address that should be
set in outgoing Ethernet frames. This is useful in case Nping can't determine
your network interface MAC address or when you want to inject traffic into the
network while hiding your network card's real address. The syntax is the same
as for --dest-mac. If you set up a bogus source MAC address you may not
receive probe replies.
--ether-type type (Ethertype)
This option sets the Ethertype field of the ethernet
frame. The Ethertype is used to indicate which protocol is encapsulated in the
payload. type can be supplied in two different ways. You can use the
official numbers listed by the IEEE[3] (e.g. --ether-type 0x0800
for IP version 4), or one of the mnemonics from the section called
“Ethernet Types”.
Ethernet Types¶
These identifiers may be used as mnemonics for the Ethertype
numbers given to the --arp-type option.
ipv4, ip, 4
Internet Protocol version 4 (type 0x0800).
ipv6, 6
Internet Protocol version 6 (type 0x86DD).
arp
Address Resolution Protocol (type 0x0806).
rarp
Reverse Address Resolution Protocol (type 0x8035).
frame-relay, frelay, fr
Frame Relay (type 0x0808).
ppp
Point-to-Point Protocol (type 0x880B).
gsmp
General Switch Management Protocol (type 0x880C).
mpls
Multiprotocol Label Switching (type 0x8847).
mps-ual, mps
Multiprotocol Label Switching with Upstream-assigned
Label (type 0x8848).
mcap
Multicast Channel Allocation Protocol (type
0x8861).
pppoe-discovery, pppoe-d
PPP over Ethernet Discovery Stage (type 0x8863).
pppoe-session, pppoe-s
PPP over Ethernet Session Stage (type 0x8864).
ctag
Customer VLAN Tag Type (type 0x8100).
epon
Ethernet Passive Optical Network (type 0x8808).
pbnac
Port-based network access control (type 0x888E).
stag
Service VLAN tag identifier (type 0x88A8).
ethexp1
Local Experimental Ethertype 1 (type 0x88B5).
ethexp2
Local Experimental Ethertype 2 (type 0x88B6).
ethoui
OUI Extended Ethertype (type 0x88B7).
preauth
Pre-Authentication (type 0x88C7).
lldp
Link Layer Discovery Protocol (type 0x88CC).
mac-security, mac-sec, macsec
Media Access Control Security (type 0x88E5).
mvrp
Multiple VLAN Registration Protocol (type 0x88F5).
mmrp
Multiple Multicast Registration Protocol (type
0x88F6).
frrr
Fast Roaming Remote Request (type 0x890D).
PAYLOAD OPTIONS¶
--data hex string (Append custom binary data
to sent packets)
This option lets you include binary data as payload in
sent packets. hex string may be specified in any of the following
formats: 0xAABBCCDDEEFF..., AABBCCDDEEFF... or
\xAA\xBB\xCC\xDD\xEE\xFF.... Examples of use are --data
0xdeadbeef and --data \xCA\xFE\x09. Note that if you specify a
number like 0x00ff no byte-order conversion is performed. Make sure you
specify the information in the byte order expected by the receiver.
--data-string string (Append custom string to
sent packets)
This option lets you include a regular string as payload
in sent packets. string can contain any string. However, note that some
characters may depend on your system's locale and the receiver may not see the
same information. Also, make sure you enclose the string in double quotes and
escape any special characters from the shell. Example: --data-string
"Jimmy Jazz...".
--data-length len (Append random data to sent
packets)
This option lets you include len random bytes of
data as payload in sent packets. len must be an integer in the range
[0–65400]. However, values higher than 1400 are not recommended because
it may not be possible to transmit packets due to network MTU
limitations.
ECHO MODE¶
The "Echo Mode" is a novel technique implemented by
Nping which lets users see how network packets change in transit, from the
host where they originated to the target machine. Basically, the Echo mode
turns Nping into two different pieces: the Echo server and the Echo client.
The Echo server is a network service that has the ability to capture packets
from the network and send a copy ("echo them") to the originating
client through a side TCP channel. The Echo client is the part that
generates such network packets, transmits them to the server, and receives
their echoed version through a side TCP channel that it has previously
established with the Echo server.
This scheme lets the client see the differences between the
packets that it sends and what is actually received by the server. By having
the server send back copies of the received packets through the side
channel, things like NAT devices become immediately apparent to the client
because it notices the changes in the source IP address (and maybe even
source port). Other devices like those that perform traffic shaping,
changing TCP window sizes or adding TCP options transparently between hosts,
turn up too.
The Echo mode is also useful for troubleshooting routing and
firewall issues. Among other things, it can be used to determine if the
traffic generated by the Nping client is being dropped in transit and never
gets to its destination or if the responses are the ones that don't get back
to it.
Internally, client and server communicate over an encrypted and
authenticated channel, using the Nping Echo Protocol (NEP), whose technical
specification can be found in
https://nmap.org/svn/nping/docs/EchoProtoRFC.txt
The following paragraphs describe the different options available
in Nping's Echo mode.
--ec passphrase, --echo-client
passphrase (Run Echo client)
This option tells Nping to run as an Echo client.
passphrase is a sequence of ASCII characters that is used used to
generate the cryptographic keys needed for encryption and authentication in a
given session. The passphrase should be a secret that is also known by the
server, and it may contain any number of printable ASCII characters.
Passphrases that contain whitespace or special characters must be enclosed in
double quotes.
When running Nping as an Echo client, most options from the
regular raw probe modes apply. The client may be configured to send specific
probes using flags like --tcp, --icmp or --udp.
Protocol header fields may be manipulated normally using the appropriate
options (e.g. --ttl, --seq, --icmp-type, etc.). The
only exceptions are ARP-related flags, which are not supported in Echo mode,
as protocols like ARP are closely related to the data link layer and its
probes can't pass through different network segments.
--es passphrase, --echo-server
passphrase (Run Echo server)
This option tells Nping to run as an Echo server.
passphrase is a sequence of ASCII characters that is used used to
generate the cryptographic keys needed for encryption and authentication in a
given session. The passphrase should be a secret that is also known by the
clients, and it may contain any number of printable ASCII characters.
Passphrases that contain whitespace or special characters must be enclosed in
double quotes. Note that although it is not recommended, it is possible to use
empty passphrases, supplying --echo-server "". However, if
what you want is to set up an open Echo server, it is better to use option
--no-crypto. See below for details.
--ep port, --echo-port
port (Set Echo TCP port number)
This option asks Nping to use the specified TCP port
number for the Echo side channel connection. If this option is used with
--echo-server, it specifies the port on which the server listens for
connections. If it is used with --echo-client, it specifies the port to
connect to on the remote host. By default, port number 9929 is used.
--nc, --no-crypto (Disable encryption and
authentication)
This option asks Nping not to use any cryptographic
operations during an Echo session. In practical terms, this means that the
Echo side channel session data will be transmitted in the clear, and no
authentication will be performed by the server or client during the session
establishment phase. When
--no-crypto is used, the passphrase supplied
with
--echo-server or
--echo-client is ignored.
This option must be specified if Nping was compiled without
openSSL support. Note that, for technical reasons, a passphrase still needs
to be supplied after the --echo-client or --echo-server flags, even though
it will be ignored.
The --no-crypto flag might be useful when setting up a public Echo
server, because it allows users to connect to the Echo server without the
need for any passphrase or shared secret. However, it is strongly
recommended to not use --no-crypto unless absolutely necessary. Public Echo
servers should be configured to use the passphrase "public" or the
empty passphrase (--echo-server "") as the use of cryptography
does not only provide confidentiality and authentication but also message
integrity.
--once (Serve one client and quit)
This option asks the Echo server to quit after serving
one client. This is useful when only a single Echo session wants to be
established as it eliminates the need to access the remote host to shutdown
the server.
--safe-payloads (Zero application data before echoing a
packet)
This option asks the Echo server to erase any application
layer data found in client packets before echoing them. When the option is
enabled, the Echo server parses the packets received from Echo clients and
tries to determine if they contain data beyond the transport layer. If such
data is found, it is overwritten with zeroes before transmitting the packets
to the appropriate Echo client.
Echo servers can handle multiple simultaneous clients running
multiple echo sessions in parallel. In order to determine which packet needs
to be echoed to which client and through which session, the Echo server uses
an heuristic algorithm. Although we have taken every security measure that
we could think of to prevent that a client receives an echoed packet that it
did not generate, there is always a risk that our algorithm makes a mistake
and delivers a packet to the wrong client. The --safe-payloads option is
useful for public echo servers or critical deployments where that kind of
mistake cannot be afforded.
The following examples illustrate how Nping's Echo mode can be
used to discover intermediate devices.
Example 2. Discovering NAT devices
# nping --echo-client "public" echo.nmap.org --udp
Starting Nping ( https://nmap.org/nping )
SENT (1.0970s) UDP 10.1.20.128:53 > 178.79.165.17:40125 ttl=64 id=32523 iplen=28
CAPT (1.1270s) UDP 80.38.10.21:45657 > 178.79.165.17:40125 ttl=54 id=32523 iplen=28
RCVD (1.1570s) ICMP 178.79.165.17 > 10.1.20.128 Port unreachable (type=3/code=3) ttl=49 id=16619 iplen=56
[...]
SENT (5.1020s) UDP 10.1.20.128:53 > 178.79.165.17:40125 ttl=64 id=32523 iplen=28
CAPT (5.1335s) UDP 80.38.10.21:45657 > 178.79.165.17:40125 ttl=54 id=32523 iplen=28
RCVD (5.1600s) ICMP 178.79.165.17 > 10.1.20.128 Port unreachable (type=3/code=3) ttl=49 id=16623 iplen=56
Max rtt: 60.628ms | Min rtt: 58.378ms | Avg rtt: 59.389ms
Raw packets sent: 5 (140B) | Rcvd: 5 (280B) | Lost: 0 (0.00%)| Echoed: 5 (140B)
Tx time: 4.00459s | Tx bytes/s: 34.96 | Tx pkts/s: 1.25
Rx time: 5.00629s | Rx bytes/s: 55.93 | Rx pkts/s: 1.00
Nping done: 1 IP address pinged in 6.18 seconds
The output clearly shows the presence of a NAT device in the
client's local network. Note how the captured packet (CAPT) differs from the
SENT packet: the source address for the original packets is in the reserved
10.0.0.0/8 range, while the address seen by the server is 80.38.10.21, the
Internet side address of the NAT device. The source port was also modified
by the device. The line starting with RCVD corresponds to the responses
generated by the TCP/IP stack of the machine where the Echo server is
run.
Example 3. Discovering a transparent
proxy
# nping --echo-client "public" echo.nmap.org --tcp -p80
Starting Nping ( https://nmap.org/nping )
SENT (1.2160s) TCP 10.0.1.77:41659 > 178.79.165.17:80 S ttl=64 id=3317 iplen=40 seq=567704200 win=1480
RCVD (1.2180s) TCP 178.79.165.17:80 > 10.0.1.77:41659 SA ttl=128 id=13177 iplen=44 seq=3647106954 win=16384 <mss 1460>
SENT (2.2150s) TCP 10.0.1.77:41659 > 178.79.165.17:80 S ttl=64 id=3317 iplen=40 seq=567704200 win=1480
SENT (3.2180s) TCP 10.0.1.77:41659 > 178.79.165.17:80 S ttl=64 id=3317 iplen=40 seq=567704200 win=1480
SENT (4.2190s) TCP 10.0.1.77:41659 > 178.79.165.17:80 S ttl=64 id=3317 iplen=40 seq=567704200 win=1480
SENT (5.2200s) TCP 10.0.1.77:41659 > 178.79.165.17:80 S ttl=64 id=3317 iplen=40 seq=567704200 win=1480
Max rtt: 2.062ms | Min rtt: 2.062ms | Avg rtt: 2.062ms
Raw packets sent: 5 (200B) | Rcvd: 1 (46B) | Lost: 4 (80.00%)| Echoed: 0 (0B)
Tx time: 4.00504s | Tx bytes/s: 49.94 | Tx pkts/s: 1.25
Rx time: 5.00618s | Rx bytes/s: 9.19 | Rx pkts/s: 0.20
Nping done: 1 IP address pinged in 6.39 seconds
In this example, the output is a bit more tricky. The absence of
error messages shows that the Echo client has successfully established an
Echo session with the server. However, no CAPT packets can be seen in the
output. This means that none of the transmitted packets reached the server.
Interestingly, a TCP SYN-ACK packet was received in response to the first
TCP-SYN packet (and also, it is known that the target host does not have
port 80 open). This behavior reveals the presence of a transparent web proxy
cache server (which in this case is an old MS ISA server).
--delay time (Delay between probes)
This option lets you control for how long will Nping wait
before sending the next probe. Like in many other ping tools, the default
delay is one second. time must be a positive integer or floating point
number. By default it is specified in seconds, however you can give an
explicit unit by appending ms for milliseconds, s for seconds, m for minutes,
or h for hours (e.g. 2.5s, 45m, 2h).
--rate rate (Send probes at a given rate)
This option specifies the number of probes that Nping
should send per second. This option and --delay are inverses; --rate
20 is the same as --delay 0.05. If both options are used, only the
last one in the parameter list counts.
MISCELLANEOUS OPTIONS¶
-h, --help (Display help)
Displays help information and exits.
-V, --version (Display version)
Displays the program's version number and quits.
-c rounds, --count
rounds (Stop after a given number of rounds)
This option lets you specify the number of times that
Nping should loop over target hosts (and in some cases target ports). Nping
calls these “rounds”. In a basic execution with only one target
(and only one target port in TCP/UDP modes), the number of rounds matches the
number of probes sent to the target host. However, in more complex executions
where Nping is run against multiple targets and multiple ports, the number of
rounds is the number of times that Nping sends a complete set of probes that
covers all target IPs and all target ports. For example, if Nping is asked to
send TCP SYN packets to hosts 192.168.1.0-255 and ports 80 and 433, then 256
× 2 = 512 packets are sent in one round. So if you
specify -c 100, Nping will loop over the different target hosts and
ports 100 times, sending a total of 256 × 2 ×
100 = 51200 packets. By default Nping runs for 5 rounds. If a
value of 0 is specified, Nping will run continuously.
-e name, --interface
name (Set the network interface to be used)
This option tells Nping what interface should be used to
send and receive packets. Nping should be able to detect this automatically,
but it will tell you if it cannot. name must be the name of an existing
network interface with an assigned IP address.
--privileged (Assume that the user is fully privileged)
Tells Nping to simply assume that it is privileged enough
to perform raw socket sends, packet sniffing, and similar operations that
usually require special privileges. By default Nping quits if such operations
are requested by a user that has no root or administrator privileges. This
option may be useful on Linux, BSD or similar systems that can be configured
to allow unprivileged users to perform raw-packet transmissions. The
NPING_PRIVILEGED environment variable may be set as an alternative to
using --privileged.
--unprivileged (Assume that the user lacks raw socket
privileges)
This option is the opposite of --privileged. It
tells Nping to treat the user as lacking network raw socket and sniffing
privileges. This is useful for testing, debugging, or when the raw network
functionality of your operating system is somehow broken. The
NPING_UNPRIVILEGED environment variable may be set as an alternative to
using --unprivileged.
--send-eth (Use raw ethernet sending)
Asks Nping to send packets at the raw ethernet (data
link) layer rather than the higher IP (network) layer. By default, Nping
chooses the one which is generally best for the platform it is running on. Raw
sockets (IP layer) are generally most efficient for Unix machines, while
ethernet frames are required for Windows operation since Microsoft disabled
raw socket support. Nping still uses raw IP packets despite this option when
there is no other choice (such as non-ethernet connections).
--send-ip (Send at raw IP level)
Asks Nping to send packets via raw IP sockets rather than
sending lower level ethernet frames. It is the complement to the
--send-eth option.
--bpf-filter filter spec --filter
filter spec (Set custom BPF filter)
This option lets you use a custom BPF filter. By default
Nping chooses a filter that is intended to capture most common responses to
the particular probes that are sent. For example, when sending TCP packets,
the filter is set to capture packets whose destination port matches the
probe's source port or ICMP error messages that may be generated by the target
or any intermediate device as a result of the probe. If for some reason you
expect strange packets in response to sent probes or you just want to sniff a
particular kind of traffic, you can specify a custom filter using the BPF
syntax used by tools like tcpdump. See the documentation at
http://www.tcpdump.org/ for more information.
-H, --hide-sent (Do not display sent packets)
This option tells Nping not to print information about
sent packets. This can be useful when using very short inter-probe delays
(i.e., when flooding), because printing information to the standard output has
a computational cost and disabling it can probably speed things up a bit.
Also, it may be useful when using Nping to detect active hosts or open ports
(e.g. sending probes to all TCP ports in a /24 subnet). In that case, users
may not want to see thousands of sent probes but just the replies generated by
active hosts.
-N, --no-capture (Do not attempt to capture
replies)
This option tells Nping to skip packet capture. This
means that packets in response to sent probes will not be processed or
displayed. This can be useful when doing flooding and network stack stress
tests. Note that when this option is specified, most of the statistics shown
at the end of the execution will be useless. This option does not work with
TCP Connect mode.
OUTPUT OPTIONS¶
-v[level], --verbose
[level] (Increase or set verbosity level)
Increases the verbosity level, causing Nping to print
more information during its execution. There are 9 levels of verbosity (-4 to
4). Every instance of
-v increments the verbosity level by one (from
its default value, level 0). Every instance of option
-q decrements the
verbosity level by one. Alternatively you can specify the level directly, as
in
-v3 or
-v-1. These are the available levels:
Level -4
No output at all. In some circumstances you may not want
Nping to produce any output (like when one of your work mates is watching over
your shoulder). In that case level -4 can be useful because although you won't
see any response packets, probes will still be sent.
Level -3
Like level -4 but displays fatal error messages so you
can actually see if Nping is running or it failed due to some error.
Level -2
Like level -3 but also displays warnings and recoverable
errors.
Level -1
Displays traditional run-time information (version, start
time, statistics, etc.) but does not display sent or received packets.
Level 0
This is the default verbosity level. It behaves like
level -1 but also displays sent and received packets and some other important
information.
Level 1
Like level 0 but it displays detailed information about
timing, flags, protocol details, etc.
Level 2
Like level 1 but displays very detailed information about
sent and received packets and other interesting information.
Level 3
Like level 2 but also displays the raw hexadecimal dump
of sent and received packets.
Level 4 and higher
Same as level 3.
-q[level], --reduce-verbosity
[level] (Decrease verbosity level)
Decreases the verbosity level, causing Nping to print
less information during its execution.
-d[level] (Increase or set debugging
level)
When even verbose mode doesn't provide sufficient data
for you, debugging is available to flood you with much more! As with the
-v, debugging is enabled with a command-line flag
-d and the
debug level can be increased by specifying it multiple times. There are 7
debugging levels (0 to 6). Every instance of
-d increments debugging
level by one. Provide an argument to
-d to set the level directly; for
example
-d4.
Debugging output is useful when you suspect a bug in Nping, or if
you are simply confused as to what Nping is doing and why. As this feature
is mostly intended for developers, debug lines aren't always
self-explanatory. You may get something like
NSOCK (1.0000s) Callback: TIMER SUCCESS for EID 12; tcpconnect_event_handler(): Received callback of type TIMER with status SUCCESS
If you don't understand a line, your only recourses are to ignore
it, look it up in the source code, or request help from the development list
(nmap-dev). Some lines are self-explanatory, but the messages become more
obscure as the debug level is increased. These are the available levels:
Level 0
Level 0. No debug information at all. This is the default
level.
Level 1
In this level, only very important or high-level debug
information will be printed.
Level 2
Like level 1 but also displays important or medium-level
debug information
Level 3
Like level 2 but also displays regular and low-level
debug information.
Level 4
Like level 3 but also displays messages only a real Nping
freak would want to see.
Level 5
Like level 4 but it enables basic debug information
related to external libraries like Nsock.
Level 6
Like level 5 but it enables full, very detailed, debug
information related to external libraries like Nsock.
BUGS¶
Like its authors, Nping isn't perfect. But you can help make it
better by sending bug reports or even writing patches. If Nping doesn't
behave the way you expect, first upgrade to the latest version available
from https://nmap.org. If the problem persists, do some research to
determine whether it has already been discovered and addressed. Try
searching for the problem or error message on Google since that aggregates
so many forums. If nothing comes of this, create an Issue on our tracker
(http://issues.nmap.org) and/or mail a bug report to
<dev@nmap.org>. If you subscribe to the nmap-dev list before posting,
your message will bypass moderation and get through more quickly. Subscribe
at https://nmap.org/mailman/listinfo/dev. Please include everything
you have learned about the problem, as well as what version of Nping you are
using and what operating system version it is running on. Other suggestions
for improving Nping may be sent to the Nmap dev mailing list as well.
If you are able to write a patch improving Nping or fixing a bug,
that is even better! Instructions for submitting patches or git pull
requests are available from
https://github.com/nmap/nmap/blob/master/CONTRIBUTING.md
Particularly sensitive issues such as a security reports may be
sent directly to Fyodor directly at <fyodor@nmap.org>. All other
reports and comments should use the dev list or issue tracker instead
because more people read, follow, and respond to those.
NOTES¶
- 1.
- official type numbers assigned by IANA
- 2.
- official numbers assigned by IANA
- 3.
- official numbers listed by the IEEE