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NPING(1) Nping Reference Guide NPING(1)
nping - Network packet generation tool / ping utility
nping [Options] {targets}
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
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.
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.
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
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.
-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].
-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 .
-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-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-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.
-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 R|S [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.
-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].
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).
--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.
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.
-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.
-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.
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
<[email protected]>. 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 <[email protected]>. All other
reports and comments should use the dev list or issue tracker
instead because more people read, follow, and respond to those.
Luis MartinGarcia <[email protected]> (http://www.luismg.com )
Fyodor <[email protected]> (https://insecure.org )
1. official type numbers assigned by IANA
http://www.iana.org/assignments/icmp-parameters
2. official numbers assigned by IANA
http://www.iana.org/assignments/arp-parameters/
3. official numbers listed by the IEEE
http://standards.ieee.org/regauth/ethertype/eth.txt
This page is part of the nmap (a network scanner) project.
Information about the project can be found at ⟨http://nmap.org/⟩.
If you have a bug report for this manual page, send it to
[email protected]. This page was obtained from the project's upstream
Git mirror of the Subversion repository
⟨https://github.com/nmap/nmap⟩ on 2024-06-14. (At that time, the
date of the most recent commit that was found in the repository
was 2024-06-13.) If you discover any rendering problems in this
HTML version of the page, or you believe there is a better or
more up-to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
[email protected]
Nping 04/23/2024 NPING(1)
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