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Langue: en

Version: 259614 (debian - 07/07/09)

Section: 1 (Commandes utilisateur)

BSD mandoc


scamper - parallel Internet measurement utility


-words [-?Pv [-c command ] ] [-p pps ] [-M monitorname ] [-s sport ] [-H holdtime ] [-o outfile ] [-O outtype ] [-i addr 1..N | listfile | -D port ]


The utility provides the ability to execute Internet measurement techniques to IPv4 and IPv6 addresses, in parallel, to fill a specified packets-per-second rate. Currently, supports the well-known traceroute and ping techniques. has three modes of operation.

First, can be supplied a list of addresses on the command line with the -i option. will then measure each of the supplied addresses, in parallel, and output the results as each task completes. Second, can be supplied a list of addresses in a listfile, one address per line. Finally, can be started as a daemon listening on a port specified with the -D option only accessible on the local host. will then accept connections to that port, where commands can be supplied to scamper.

The options are as follows:

prints a list of command line options and a synopsis of each.
tells scamper to use the operating system's datalink support to obtain more accurate transmit and receive timestamps for probes. This corresponds to bpf(4) on BSD systems, and packet(7) on Linux systems. Datalink timestamps exclude the effects of route-lookup delays, as well as overheads in a packet making it to and from the network interface.
causes to output version information and exit.
-c command
specifies the command for to use by default. The current choices for this option are trace and ping. uses trace by default.
-p pps
specifies the target packets-per-second rate for to reach. By default, this value is 20.
-M monitorname
specifies the canonical name of machine where is run. This value is used when recording the output in a warts(5) output file.
-s sport
specifies the default source port value for to use. By default, this value is the least significant 15 bits of the process id with the 16th bit set.
-H holdtime
specifies how long to wait after a measurement has completed for any final responses that were delayed.
-o outfile
specifies the default output file to write measurement results to. By default, stdout is used.
-O outtype
specifies the default output file format to use. By default, ASCII output is used. However, warts(5) provides a binary file format that records much more meta data and detail.
-i addr 1..N
specifies the addresses to probe, on the command line.
specifies the input file to read for target addresses.
-D port
specifies that starts as a daemon, listening on the specified port.


The following variation of the traceroute(8) options are available when using the trace command:

trace -words [-MQ ] [-d dport ] [-f firsthop ] [-g gaplimit ] [-l loops ] [-m maxttl ] [-P method ] [-q attempts ] [-s sport ] [-t tos ] [-w wait ]

-P method
specifies the traceroute method to use. currently supports five different probe methods: UDP, ICMP, TCP, UDP-paris, and ICMP-paris. By default, UDP is used.
-d dport
specifies the base destination port value to use for UDP-based and TCP-based traceroute methods. For ICMP-based methods, this option has no effect.
-s sport
specifies the source port value to use. For ICMP-based methods, this option specifies the ICMP identifier to use.
-f firsthop
specifies the TTL or HLIM value to begin probing with. By default, a first hop of one is used.
-g gaplimit
specifies the number of unresponsive hops permitted until a check is made to see if the destination will respond. By default, a gap limit of 5 hops is used. Setting the gap limit to 0 disables the gap limit.
-m maxttl
specifies the maximum TTL or HLIM value that will be probed. By default, a maxttl of 32 is used.
-l loops
specifies the maximum number of loops permitted until probing stops. By default, a value of one is used. A value of zero disables loop checking.
-q attempts
specifies the maximum number of attempts to obtain a response per hop. By default, a value of two is used.
specifies that all allocated probes are sent, regardless of how many responses have been received.
-w wait
specifies how long to wait, in seconds, for a reply. By default, a value of 5 is used.
-t tos
specifies the value to set in the IP ToS/DSCP + ECN byte. By default, this byte is set to zero.
specifies that path MTU discovery should be attempted for the path when the initial traceroute completes.


The following variation of the ping(8) options are available when using the ping command:

ping -words [-c probecount ] [-i wait ] [-m ttl ] [-o replycount ] [-p pattern ] [-s size ] [-z tos ]

-c probecount
specifies the number of probes to send before exiting. By default, a value of 4 is used.
-i wait
specifies the length of time to wait, in seconds, between probes. By default, a value of 1 is used.
-m ttl
specifies the TTL value to use for outgoing packets. By default, a value of 64 is used.
-o replycount
specifies the number of replies required at which time probing may cease. By default, all probes are sent.
-p pattern
specifies the pattern, in hex, to use in probes. Up to 16 bytes may be specified. By default, each probe's bytes are zeroed.
-s size
specifies the size of the probes to send. The probe size includes the length of the IP and ICMP headers. By default, a probe size of 84 bytes is used for IPv4 pings, and 56 bytes for IPv6 pings.
-z tos
specifies the value to use in the IPv4 ToS/DSCP + ECN byte. By default, this byte is set to zero.


has two data output formats. The first is a human-readable format suitable for one-off data collection and measurement. The second, known as warts is a binary format that records much more meta-data and is more precise than the human-readable format.

is designed for Internet-scale measurement, where large lists of targets are supplied for probing. has the ability to probe multiple lists simultaneously, with each having a mix rate that specifies the priority of the list. can also make multiple cycles over a list of addresses.

When writing output to a warts file, records details of the list and cycle that each measurement task belongs to.


When started with the -D option, allows inter-process communication via a TCP socket bound to the supplied port on the local host. This socket is useful for controlling the operation of a long-lived process. A client may interact with scamper by using telnet(1) to open a connection to the supplied port.

The following control socket commands are available.

The exit command closes the current control socket connection.
get argument
The get command returns the current setting for the supplied argument. Valid argument values are: holdtime, monitorname, pid, pps, sport, version.
set argument ...
The set command sets the current setting for the supplied argument. Valid argument values are: holdtime, monitorname, pps.
source argument ...
add arguments
The source add command allows a new input source to be added. It accepts the following arguments:
name string
The name of the source. This parameter is mandatory.
descr string
An optional string describing the source.
command string
The command to execute for each address supplied. If not supplied, the default command is used.
list_id uint32_t
An optional numeric list identifier, assigned by a human. If not supplied, a value of zero is used.
cycle_id uint32_t
An optional numeric initial cycle identifier to use, assigned by a human. If not supplied, a value of one is used.
priority uint32_t
An optional numeric value that specifies the mix rate of measurements from the source compared to other sources. If not supplied, a mix rate of one is used. A value of zero causes the source to be created, but not actively used.
adhoc [on | off ]
An optional parameter that specifies if the source is adhoc (on) or managed (off). An adhoc source is supplied addresses to probe using control socket commands. A managed source is one that is supplied addresses to probe from a file. A managed source handles cycling and reloading the file as necessary. If not supplied, an adhoc source is created.
outfile string
The name of the output file to write results to, previously defined with outfile open If not supplied, the default output file is used.
file string
The name of the input file to read target addresses from. This parameter is mandatory if the source is a managed source.
cycles integer
The number of cycles to make over the target address file. If zero, will loop indefinitely over the file. This parameter is ignored unless a managed source is defined.
autoreload [on | off ]
This parameter specifies if the target address file should be re-read whenever a cycle is completed, or if the same set of target addresses as the previous cycle should be used. If not specified, the file is not automatically reloaded at cycle time.
update name arguments
The source update command allows some properties of an existing source to be modified. The source to update is specified with the name parameter. Valid parameters are: autoreload, cycles, and priority.
list ...
The source list command provides a listing of all currently defined sources. The optional third name parameter restricts the listing to the source specified.
cycle name
The source cycle command manually inserts a cycle marker in an adhoc source.
delete name
The source delete command deletes the named source, if possible.
outfile argument ...
The outfile commands provide the ability to manage output files. It accepts the following arguments:
open ...
The outfile open command allows a new output file to be defined. It accepts the following parameters:
name alias
The alias of the output file. This parameter is mandatory.
file string
The filename of the output file. This parameter is mandatory.
mode [truncate | append ]
How the file will be opened. If the append mode is used, any existing file with the specified name will be appended to. If the truncate mode is used, any existing file will be truncated when it is opened.
close alias
The outfile close command allows an existing output file to be closed. The mandatory alias parameter specifies which output file to close. An output file that is currently referenced is not able to be closed. To close a file that is currently referenced, a new outfile must be opened, and then the outfile swap command be used.
swap alias1 alias2
The outfile swap command swaps the file associated with each output file.
The outfile list command outputs a list of the existing outfiles.
observe sources
This command allows for monitoring of source events. When executed, the control socket will then supply event notices whenever a source is added, updated, deleted, finished, or cycled. Each event is prefixed with a count of the number of seconds elapsed since the Unix epoch. The following examples illustrate the event monitoring capabilities:
EVENT 1169065640 source add name 'foo' list_id 5 priority 1
EVENT 1169065641 source update 'foo' priority 15
EVENT 1169065642 source cycle 'bar' id 2
EVENT 1169065650 source finish 'bar'
EVENT 1169065661 source delete 'foo'
shutdown argument
The shutdown argument allows the process to be exited cleanly. The following arguments are supported
The shutdown done command requests that shuts down when the current tasks, as well as all remaining cycles, have completed.
The shutdown flush command requests that flushes all remaining tasks queued with each list, finishes all current tasks, and then shuts down.
The shutdown now command causes to shutdown immediately. Unfinished tasks are purged.
The shutdown cancel command cancels any pending shutdown.


To use the default traceroute command to trace the path to

scamper -i

To infer Path MTU changes in the network and associate them with a traceroute path:

scamper -c "trace -M" -i

To use paris UDP traceroute, using 3 probes per hop, sending all probes:

scamper -c "trace -P UDP-paris -q 3 -Q" -i

To ping a series of addresses defined in filename probing each address 10 times:

scamper -c "ping -c 10" filename


ping(8), sc_analysis_dump1, traceroute(8), warts(5), warts-dump1


is written by Matthew Luckie <>, member of the WAND network research group at the University of Waikato.


development was initially funded by the WIDE project in association with CAIDA. CAIDA actively support development.
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