TCPREPLAY

Section: Programmer's Manual (1)
Updated: 2008-05-02
Index Return to Main Contents
 

NAME

tcpreplay - Replay network traffic stored in pcap files  

SYNOPSIS

tcpreplay [-flag [value]]... [--opt-name [[=| ]value]]...
<pcap_file(s)>

tcpreplay is a tool for replaying network traffic from files saved with tcpdump or other tools which write pcap(3) files.  

DESCRIPTION

This manual page documents, briefly, the tcpreplay command. The basic operation of tcpreplay is to resend all packets from the input file(s) at the speed at which they were recorded, or a specified data rate, up to as fast as the hardware is capable.

Optionally, the traffic can be split between two interfaces, written to files, filtered and edited in various ways, providing the means to test firewalls, NIDS and other network devices.

For more details, please see the Tcpreplay Manual at: http://tcpreplay.synfin.net/trac/wiki/manual  

OPTIONS

-d number, --dbug=number
Enable debugging output. This option may appear up to 1 times. This option takes an integer number as its argument. The value of number is constrained to being:
in the range  0 through 5
The default number for this option is:
    
 0

If configured with --enable-debug, then you can specify a verbosity level for debugging output. Higher numbers increase verbosity.

-q, --quiet
Quiet mode.

Print nothing except the statistics at the end of the run

-T string, --timer=string
Select packet timing mode: select, ioport, rdtsc, gtod, nano, abstime. This option may appear up to 1 times. The default string for this option is:
    
 gtod

Allows you to select the packet timing method to use:

nano - Use nanosleep() API

select - Use select() API

ioport - Write to the i386 IO Port 0x80

rdtsc - Use the x86/x86_64/PPC RDTSC

gtod [default] - Use a gettimeofday() loop

abstime - Use OS X's AbsoluteTime API

--sleep-accel=number
Reduce the amount of time to sleep by specified usec. This option takes an integer number as its argument. The default number for this option is:
    
 0

Reduce the amount of time we would normally sleep between two packets by the specified number of usec. This provides a "fuzz factor" to compensate for running on a non-RTOS and other processes using CPU time. Default is disabled.

--rdtsc-clicks=number
Specify the RDTSC clicks/usec. This option may appear up to 1 times. This option takes an integer number as its argument. The default number for this option is:
    
 0

Override the calculated number of RDTSC clicks/usec which is often the speed of the CPU in Mhz. Only useful if you specified --timer=rdtsc

-v, --verbose
Print decoded packets via tcpdump to STDOUT. This option may appear up to 1 times.

-A string, --decode=string
Arguments passed to tcpdump decoder. This option may appear up to 1 times. This option must appear in combination with the following options: verbose.

When enabling verbose mode (-v) you may also specify one or more additional arguments to pass to tcpdump to modify the way packets are decoded. By default, -n and -l are used. Be sure to quote the arguments like: -A "-axxx" so that they are not interpreted by tcpreplay. Please see the tcpdump(1) man page for a complete list of options.

-K, --enable-file-cache
Enable caching of packets to internal memory. This option must appear in combination with the following options: loop.

Cache pcap file(s) the first time they are cached in RAM so that subsequent loops don't incurr any disk I/O latency in order to increase performance. Make sure you have enough free RAM to store the entire pcap file(s) in memory or the system will swap and performance will suffer.

-c string, --cachefile=string
Split traffic via a tcpprep cache file. This option may appear up to 1 times.

-i string, --intf1=string
Server/primary traffic output interface. This option may appear up to 1 times.

-I string, --intf2=string
Client/secondary traffic output interface. This option may appear up to 1 times. This option must appear in combination with the following options: cachefile.

-l number, --loop=number
Loop through the capture file X times. This option may appear up to 1 times. This option takes an integer number as its argument. The value of number is constrained to being:
greater than or equal to 0
The default number for this option is:
    
 1

--pktlen
Override the snaplen and use the actual packet len. This option may appear up to 1 times.

By default, tcpreplay will send packets based on the size of the "snaplen" stored in the pcap file which is usually the correct thing to do. However, occasionally, tools will store more bytes then told to. By specifying this option, tcpreplay will ignore the snaplen field and instead try to send packets based on the original packet length. Bad things may happen if you specify this option.

-L number, --limit=number
Limit the number of packets to send. This option may appear up to 1 times. This option takes an integer number as its argument. The value of number is constrained to being:
greater than or equal to 1
The default number for this option is:
    
 -1

By default, tcpreplay will send all the packets. Alternatively, you can specify a maximum number of packets to send.

-x string, --multiplier=string
Modify replay speed to a given multiple. This option may appear up to 1 times. This option must not appear in combination with any of the following options: pps, mbps, oneatatime, topspeed.

Specify a floating point value to modify the packet replay speed. Examples:

        2.0 will replay traffic at twice the speed captured
        0.7 will replay traffic at 70% the speed captured
-p number, --pps=number
Replay packets at a given packets/sec. This option may appear up to 1 times. This option must not appear in combination with any of the following options: multiplier, mbps, oneatatime, topspeed. This option takes an integer number as its argument.

-M string, --mbps=string
Replay packets at a given Mbps. This option may appear up to 1 times. This option must not appear in combination with any of the following options: multiplier, pps, oneatatime, topspeed.

Specify a floating point value for the Mbps rate that tcpreplay should send packets at.

-t, --topspeed
Replay packets as fast as possible. This option must not appear in combination with any of the following options: mbps, multiplier, pps, oneatatime.

-o, --oneatatime
Replay one packet at a time for each user input. This option must not appear in combination with any of the following options: mbps, pps, multiplier, topspeed.

Allows you to step through one or more packets at a time.

-P, --pid
Print the PID of tcpreplay at startup.

-V, --version
Print version information.

-h, --less-help
Display less usage information and exit.

-H, --help
Display usage information and exit.
-!, --more-help
Extended usage information passed thru pager.
- [rcfile], --save-opts[=rcfile]
Save the option state to rcfile. The default is the last configuration file listed in the OPTION PRESETS section, below.
- rcfile, --load-opts=rcfile, --no-load-opts
Load options from rcfile. The no-load-opts form will disable the loading of earlier RC/INI files. --no-load-opts is handled early, out of order.
 

OPTION PRESETS

Any option that is not marked as not presettable may be preset by loading values from configuration ("RC" or ".INI") file(s). The homerc file is "$$/", unless that is a directory. In that case, the file ".tcpreplayrc" is searched for within that directory.  

SIGNALS

tcpreplay understands the following signals:

SIGUSR1 Suspend tcpreplay

SIGCONT Restart tcpreplay

 

SEE ALSO

tcpreplay-edit(1), tcpdump(1), tcpprep(1), tcprewrite(1), libnet(3)

 

BUGS

tcpreplay can only send packets as fast as your computer's interface, processor, disk and system bus will allow.

Packet timing at high speeds is a black art and very OS/CPU dependent.

Replaying captured traffic may simulate odd or broken conditions on your network and cause all sorts of problems.

In most cases, you can not replay traffic back to/at a server.

Some operating systems by default do not allow for forging source MAC addresses. Please consult your operating system's documentation and the tcpreplay FAQ if you experience this issue.  

AUTHOR

Copyright 2000-2008 Aaron Turner

For support please use the tcpreplay-users@lists.sourceforge.net mailing list.

The latest version of this software is always available from: http://tcpreplay.synfin.net/

Released under the Free BSD License.

This manual page was AutoGen-erated from the tcpreplay option definitions.


 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
OPTION PRESETS
SIGNALS
SEE ALSO
BUGS
AUTHOR

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