TCPREPLAY(1)

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. Examples:
        --portmap=80:8000 --portmap=8080:80    # 80->8000 and 8080->80
        --portmap=8000,8080,88888:80           # 3 different ports become 80
        --portmap=8000-8999:80                 # ports 8000 to 8999 become 80

-s number, --seed=number
    Randomize src/dst IPv4/v6 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 IPv4/v6 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 IPv4/v6 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. IPv4 Example:
        --pnat=192.168.0.0/16:10.77.0.0/16,172.16.0.0/12:10.1.0.0/24
    IPv6 Example:
        --pnat=[2001:db8::/32]:[dead::/16],[2001:db8::/32]:[::ffff:0:0/96]

-S string, --srcipmap=string
    Rewrite source IPv4/v6 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/v6 header.

-D string, --dstipmap=string
    Rewrite destination IPv4/v6 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/v6 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 IPv4/v6 addresses which will be used to rewrite all traffic to appear to be between the two IP's. IPv4 Example:
        --endpoints=172.16.0.1:172.16.0.2
    IPv6 Example:
        --endpoints=[2001:db8::dead:beef]:[::ffff:0:0:ac:f:0:2]

-b, --skipbroadcast
    Skip rewriting broadcast/multicast IPv4/v6 addresses.

    By default --seed, --pnat and --endpoints will rewrite
    broadcast and multicast IPv4/v6 and MAC addresses.    Setting this flag
    will keep broadcast/multicast IPv4/v6 and MAC addresses from being rewritten.

-C, --fixcsum
    Force recalculation of IPv4/TCP/UDP header checksums.

    Causes each IPv4/v6 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 (--fixlen=pad) or when truncating (--mtu-trunc).

--mtu-trunc
    Truncate packets larger then specified MTU. This option may appear up to 1 times.

    Similar to --fixlen, this option will truncate data in packets from Layer 3 and above to be no larger then the MTU.

-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/v6 TTL/Hop Limit.

    Allows you to modify the TTL/Hop Limit of all the IPv4/v6 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.

--tclass=number
    Set the IPv6 Traffic Class 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 IPv6 Traffic Class field.

--flowlabel=number
    Set the IPv6 Flow Label. 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 1048575

    Allows you to override the 20bit IPv6 Flow Label field. Has no effect on 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/v6 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.

--preload-pcap
    Preloads packets into RAM before sending.

    This option loads the specified pcap(s) into RAM before starting to send in order to improve replay performance while introducing a startup performance hit. Preloading can be used with or without --loop and implies --enable-file-cache.

-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.

--stats=number
    Print statistics every X seconds. This option takes an integer number as its argument. The value of number is constrained to being:
    greater than or equal to 1

    Note that this is very much a "best effort" and long delays between sending packets may cause equally long delays between printing statistics.

-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 2000-2010 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.