NPING(1) Nping Reference Guide NPING(1)
nping - Network packet generation tool / ping utility
SYNOPSIS top
nping [Options] {targets}
DESCRIPTION top
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
OPTIONS SUMMARY top
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 0.5.59BETA1 ( 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; 10.0.0-255.1-254
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.
--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 top
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 top
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 top
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 top
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 top
-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 top
-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 top
-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 top
--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 top
--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 top
-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.
--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
http://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 top
-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 top
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 top
--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 top
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).
TIMING AND PERFORMANCE OPTIONS top
--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 top
-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 top
-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 author, 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 Nmap version
available from https://nmap.org/download.html . If the problem
persists, do some research to determine whether it has already been
discovered and addressed. Try searching for the error message on our
search page at http://insecure.org/search.html or at Google. Also try
browsing the nmap-dev archives at http://seclists.org/ Read this full
manual page as well. If nothing comes out of this, mail a bug report
to <dev@nmap.org>. Please include everything you have learned about
the problem, as well as what version of Nping you are running and
what operating system version it is running on. Problem reports and
Nping usage questions sent to <dev@nmap.org> are far more likely to
be answered than those sent to Fyodor directly. 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 .
Code patches to fix bugs are even better than bug reports. Basic
instructions for creating patch files with your changes are available
at https://svn.nmap.org/nmap/HACKING . Patches may be sent to nmap-dev
(recommended) or to any of the authors listed in the next section
directly.
AUTHORS top
Luis MartinGarcia <luis.mgarc@gmail.com> (http://www.luismg.com )
Fyodor <fyodor@nmap.org> (http://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
COLOPHON top
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 dev@nmap.org.
This page was obtained from the project's upstream Subversion reposi‐
tory ⟨https://svn.nmap.org/nmap⟩ on 2017-07-05. 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
man-pages@man7.org