TCPREPLAY

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
OPTION PRESETS
SIGNALS
SEE ALSO
BUGS
AUTHOR

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 briefly documents 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

−r string, −-portmap=string

Rewrite TCP/UDP ports. This option may appear up to 1 times.

Specify a list of comma delimited port mappingings consisting of colon delimited port number pairs. Each colon delimited port pair consists of the port to match followed by the port number to rewrite.

Example:
−-portmap=80:8000,8080:80

−s number, −-seed=number

Randomize src/dst IP addresses w/ given seed. This option may appear up to 1 times. This option takes an integer number as its argument.

Causes the source and destination IP addresses to be pseudo randomized but still maintain client/server relationships. Since the randomization is deterministic based on the seed, you can reuse the same seed value to recreate the traffic.

−N string, −-pnat=string

Rewrite IP addresses using pseudo-NAT. This option may appear up to 2 times. This option must not appear in combination with any of the following options: srcipmap.

Takes a comma delimited series of colon delimited CIDR netblock pairs. Each netblock pair is evaluated in order against the IP addresses. If the IP address in the packet matches the first netblock, it is rewriten using the second netblock as a mask against the high order bits.

Example:
−-pnat=192.168.0.0/16:10.77.0.0/16,172.16.0.0/12:10.1.0.0/24

−S string, −-srcipmap=string

Rewrite source IP addresses using pseudo-NAT. This option may appear up to 1 times. This option must not appear in combination with any of the following options: pnat.

Works just like the −-pnat option, but only affects the source IP addresses in the IPv4 header.

−D string, −-dstipmap=string

Rewrite destination IP addresses using pseudo-NAT. This option may appear up to 1 times. This option must not appear in combination with any of the following options: pnat.

Works just like the −-pnat option, but only affects the destination IP addresses in the IPv4 header.

−e string, −-endpoints=string

Rewrite IP addresses to be between two endpoints. This option may appear up to 1 times. This option must appear in combination with the following options: cachefile.

Takes a pair of colon delimited IP addresses which will be used to rewrite all traffic to appear to be between the two IP’s.

Example:
−-endpoints=172.16.0.1:172.16.0.2

−b, −-skipbroadcast

Skip rewriting broadcast/multicast IP’s.

By default −-seed, −-pnat and −-endpoints will rewrite broadcast and multicast IP and MAC addresses. Setting this flag will keep broadcast/multicast IP and MAC addresses from being rewritten.

−C, −-fixcsum

Force recalculation of IP/TCP/UDP checksums.

Causes each IP packet to have it’s checksums recalcualted and fixed. Automatically enabled for packets modified with --seed, --pnat, --endpoints or --fixlen.

−m number, −-mtu=number

Override default MTU length (1500 bytes). 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 1 through MAXPACKET

Override the default 1500 byte MTU size for determining the maximum padding length.

−E, −-efcs

Remove Ethernet checksums (FCS) from end of frames.

Note, this option is pretty dangerous! We don’t actually check to see if a FCS actually exists in the frame, we just blindly delete the last two bytes. Hence, you should only use this if you know know that your OS provides the FCS when reading raw packets.

−-ttl=string

Modify the IPv4 TTL.

Allows you to modify the TTL of all the IPv4 packets. Specify a number to hard-code the value or +/-value to increase or decrease by the value provided (limited to 1-255).

Examples:
−-ttl=10
−-ttl=+7
−-ttl=-64

−-tos=number

Set the IPv4 TOS/DiffServ/ECN byte. 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 255

Allows you to override the TOS (also known as DiffServ/ECN) value in IPv4 packets.

−F string, −-fixlen=string

Pad or truncate packet data to match header length. This option may appear up to 1 times.

Packets may be truncated during capture if the snaplen is smaller then the packet. This option allows you to modify the packet to pad the packet back out to the size stored in the IPv4 header or rewrite the IP header total length to reflect the stored packet length.

pad Truncated packets will be padded out so that the packet length matches the IPv4 total length

trunc Truncated packets will have their IPv4 total length field rewritten to match the actual packet length

del Delete the packet

−-skipl2broadcast

Skip rewriting broadcast/multicast Layer 2 addresses.

By default, editing Layer 2 addresses will rewrite broadcast and multicast MAC addresses. Setting this flag will keep broadcast/multicast MAC addresses from being rewritten.

−-dlt=string

Override output DLT encapsulation. This option may appear up to 1 times.

By default, no DLT (data link type) conversion will be made. To change the DLT type of the output pcap, select one of the following values:

enet Ethernet aka DLT_EN10MB

hdlc Cisco HDLC aka DLT_C_HDLC

user User specified Layer 2 header and DLT type

−-enet-dmac=string

Override destination ethernet MAC addresses. This option may appear up to 1 times.

Takes a pair of comma deliminated ethernet MAC addresses which will replace the destination MAC address of outbound packets. The first MAC address will be used for the server to client traffic and the optional second MAC address will be used for the client to server traffic.

Example:
−-enet-dmac=00:12:13:14:15:16,00:22:33:44:55:66

−-enet-smac=string

Override source ethernet MAC addresses. This option may appear up to 1 times.

Takes a pair of comma deliminated ethernet MAC addresses which will replace the source MAC address of outbound packets. The first MAC address will be used for the server to client traffic and the optional second MAC address will be used for the client to server traffic.

Example:
−-enet-smac=00:12:13:14:15:16,00:22:33:44:55:66

−-enet-vlan=string

Specify ethernet 802.1q VLAN tag mode. This option may appear up to 1 times.

Allows you to rewrite ethernet frames to add a 802.1q header to standard 802.3 ethernet headers or remove the 802.1q VLAN tag information.

add Rewrites the existing 802.3 ethernet header as an 802.1q VLAN header

del Rewrites the existing 802.1q VLAN header as an 802.3 ethernet header

−-enet-vlan-tag=number

Specify the new ethernet 802.1q VLAN tag value. This option may appear up to 1 times. This option must appear in combination with the following options: enet-vlan. This option takes an integer number as its argument. The value of number is constrained to being:

in the range 0 through 4095

−-enet-vlan-cfi=number

Specify the ethernet 802.1q VLAN CFI value. This option may appear up to 1 times. This option must appear in combination with the following options: enet-vlan. This option takes an integer number as its argument. The value of number is constrained to being:

in the range 0 through 1

−-enet-vlan-pri=number

Specify the ethernet 802.1q VLAN priority. This option may appear up to 1 times. This option must appear in combination with the following options: enet-vlan. This option takes an integer number as its argument. The value of number is constrained to being:

in the range 0 through 7

−-hdlc-control=number

Specify HDLC control value. This option may appear up to 1 times. This option takes an integer number as its argument.

The Cisco HDLC header has a 1 byte "control" field. Apparently this should always be 0, but if you can use any 1 byte value.

−-hdlc-address=number

Specify HDLC address. This option may appear up to 1 times. This option takes an integer number as its argument.

The Cisco HDLC header has a 1 byte "address" field which has two valid values:

0x0F Unicast

0xBF Broadcast
You can however specify any single byte value.

−-user-dlt=number

Set output file DLT type. This option may appear up to 1 times. This option takes an integer number as its argument.

Set the DLT value of the output pcap file.

−-user-dlink=string

Rewrite Data-Link layer with user specified data. This option may appear up to 2 times.

Provide a series of comma deliminated hex values which will be used to rewrite or create the Layer 2 header of the packets. The first instance of this argument will rewrite both server and client traffic, but if this argument is specified a second time, it will be used for the client traffic.

Example:
−-user-dlink=01,02,03,04,05,06,00,1A,2B,3C,4D,5E,6F,08,00

−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.

−-listnics

List available network interfaces and exit.

−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.

−-pps-multi=number

Number of packets to send for each time interval. This option must appear in combination with the following options: pps. 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

When trying to send packets at very high rates, the time between each packet can be so short that it is impossible to accurately sleep for the required period of time. This option allows you to send multiple packets at a time, thus allowing for longer sleep times which can be more accurately implemented.

−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.