Provided by: scamper_20070523n-1_i386
scamper - parallel Internet measurement utility
scamper [-?Pv] [-c command] [-p pps] [-M monitorname] [-s sport]
[-H holdtime] [-o outfile] [-O outtype]
[-i addr 1..N | listfile | -D port]
The scamper 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, scamper supports the well-known
traceroute and ping techniques. scamper has three modes of operation.
First, scamper can be supplied a list of addresses on the command line
with the -i option. scamper will then measure each of the supplied
addresses, in parallel, and output the results as each task completes.
Second, scamper can be supplied a list of addresses in a listfile, one
address per line. Finally, scamper can be started as a daemon listening
on a port specified with the -D option only accessible on the local host.
scamper 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.
-P tells scamper to use the operating system’s datalink support to
obtain more accurate transmit and receive timestamps for scamper
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.
-v causes scamper to output version information and exit.
specifies the command for scamper to use by default. The current
choices for this option are trace and ping. scamper uses trace
-p pps specifies the target packets-per-second rate for scamper to
reach. By default, this value is 20.
specifies the canonical name of machine where scamper is run.
This value is used when recording the output in a warts(5) output
specifies the default source port value for scamper to use. By
default, this value is the least significant 15 bits of the
process id with the 16th bit set.
specifies how long to wait after a measurement has completed for
any final responses that were delayed.
specifies the default output file to write measurement results
to. By default, stdout is used.
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.
specifies that scamper starts as a daemon, listening on the
The following variation of the traceroute(8) options are available when
using the scamper trace command:
trace [-MQ] [-d dport] [-f firsthop] [-g gaplimit] [-l loops] [-m maxttl]
[-P method] [-q attempts] [-s sport] [-t tos] [-w wait]
specifies the traceroute method to use. scamper currently
supports five different probe methods: UDP, ICMP, TCP, UDP-paris,
and ICMP-paris. By default, UDP is used.
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.
specifies the source port value to use. For ICMP-based methods,
this option specifies the ICMP identifier to use.
specifies the TTL or HLIM value to begin probing with. By
default, a first hop of one is used.
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.
specifies the maximum TTL or HLIM value that will be probed. By
default, a maxttl of 32 is used.
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.
specifies the maximum number of attempts to obtain a response per
hop. By default, a value of two is used.
-Q specifies that all allocated probes are sent, regardless of how
many responses have been received.
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.
-M 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 scamper ping command:
ping [-c probecount] [-i wait] [-m ttl] [-o replycount] [-p pattern]
[-s size] [-z tos]
specifies the number of probes to send before exiting. By
default, a value of 4 is used.
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.
specifies the number of replies required at which time probing
may cease. By default, all probes are sent.
specifies the pattern, in hex, to use in probes. Up to 16 bytes
may be specified. By default, each probe’s bytes are zeroed.
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
-z tos specifies the value to use in the IPv4 ToS/DSCP + ECN byte. By
default, this byte is set to zero.
DATA COLLECTION FEATURES
scamper 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.
scamper is designed for Internet-scale measurement, where large lists of
targets are supplied for probing. scamper has the ability to probe
multiple lists simultaneously, with each having a mix rate that specifies
the priority of the list. scamper can also make multiple cycles over a
list of addresses.
When writing output to a warts file, scamper records details of the list
and cycle that each measurement task belongs to.
When started with the -D option, scamper 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 scamper 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.
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 ...
The source add command allows a new input source to be added.
It accepts the following arguments:
The name of the source. This parameter is mandatory.
An optional string describing the source.
The command to execute for each address supplied. If not
supplied, the default command is used.
An optional numeric list identifier, assigned by a human.
If not supplied, a value of zero is used.
An optional numeric initial cycle identifier to use,
assigned by a human. If not supplied, a value of one is
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
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.
The name of the output file to write results to,
previously defined with outfile open. If not supplied,
the default output file is used.
The name of the input file to read target addresses from.
This parameter is mandatory if the source is a managed
The number of cycles to make over the target address file.
If zero, scamper will loop indefinitely over the file.
This parameter is ignored unless a managed source is
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,
The source list command provides a listing of all currently
defined sources. The optional third name parameter restricts
the listing to the source specified.
The source cycle command manually inserts a cycle marker in an
The source delete command deletes the named source, if
outfile argument ...
The outfile commands provide the ability to manage output files. It
accepts the following arguments:
The outfile open command allows a new output file to be
defined. It accepts the following parameters:
The alias of the output file. This parameter is
The filename of the output file. This parameter is
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.
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
The outfile list command outputs a list of the existing
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
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’
The shutdown argument allows the scamper process to be exited
cleanly. The following arguments are supported
The shutdown done command requests that scamper shuts down when
the current tasks, as well as all remaining cycles, have
The shutdown flush command requests that scamper flushes all
remaining tasks queued with each list, finishes all current
tasks, and then shuts down.
now The shutdown now command causes scamper 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 192.168.1.1:
scamper -i 192.168.1.1
To infer Path MTU changes in the network and associate them with a
scamper -c "trace -M" -i 192.168.1.1
To use paris UDP traceroute, using 3 probes per hop, sending all probes:
scamper -c "trace -P UDP-paris -q 3 -Q" -i 192.168.1.1
To ping a series of addresses defined in filename, probing each address
scamper -c "ping -c 10" filename
ping(8), sc_analysis_dump(1), traceroute(8), warts(5), warts-dump(1)
scamper is written by Matthew Luckie <firstname.lastname@example.org>, member of the
WAND network research group at the University of Waikato.
scamper development was initially funded by the WIDE project in
association with CAIDA. CAIDA actively support scamper development.