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packit(8) Network packet generator and capture tool packit(8)

NAME

Packit - network packet generator and capture tool

SYNOPSIS

Packet capture:


  packit -m capture [-cGHnvsX] [-i interface] [-r|-w file] expression
Packet injection:


  packit -m inject [-t protocol] [-aAbcCdDeFgGhHIjJkKlLmMnNoOpPqQrRsSTuUvwWxXyYzZ] [-i interface]

DESCRIPTION

Packit is a network auditing tool. It's value is derived from its ability to customize, inject, monitor, and manipulate IP traffic. By allowing you to define (spoof) all TCP, UDP, ICMP, IP, ARP, RARP and Ethernet header options, Packit can be useful to test firewalls, intrusion detection systems, port scanning, simulating network traffic and general TCP/IP auditing. Packit is also an excellent tool for learning TCP/IP.

PACKIT BASE OPTIONS

Select a runtime mode. Currently supported modes are capture, inject and trace. The default mode is inject.

PACKET CAPTURE OPTIONS

Packet capture options are as follows:

Specify the number of packets to capture.
Display link-layer header data.
Display the timestamp in GMT rather than localtime.
Listen on interface. If unspecified, packit will use the lowest numbered device in the 'up' state (excluding loopback).
Do not resolve host addresses to names but resolve ports numbers. Disables DNS lookups.
Do not resolve ports numbers to their protocol names but resolve host addresses.
Do not resolve host addresses or port numbers.
Read packet data from tcpdump formatted binary log file. Example: a file created with -w option.
Read snaplen bytes of data from each packet rather than the default of 68.
Enables verbose packet capture.
Write the raw packets to file rather than displaying time to stderr.
Display hexadecimal & ascii dump of each packet up to snap length bytes.
Selects which packets should be displayed. If no expression is given, all packets are displayed. This option is based in pcap library. See the pcap-filter(7) manpage for more detailed information.

PACKET INJECTION AND TRACE

Packet injection is used to define and inject a network traffic onto your network. You have the ability to define essentially any ARP, IP, TCP, UDP, ICMP and Ethernet header value. This can be valuable in a number of ways, including testing firewalls, intrusion detection systems, simulating traffic flow and general TCP/IP auditing.

CHOOSE A PROTOCOL

Specify the type of packet to inject. Supported values are: ARP, RARP, TCP, UDP and ICMP. This option defaults to TCP in inject mode and to ICMP in trace mode.

PACKET INJECTION AND TRACE GENERAL

This section documents the operational command-line options.

The value of count is the total number of packets we would like to inject (a count value of 0 means forever).
Specifies the number of packets to inject every interval (defined by -w). A burst rate of 0 will send packets as quickly as possible.
Host response mode. Enabling this option will print any packet you inject and then wait to see if the remote host responds. See -H option for timeout.
Specify the timeout value (in seconds) to use with '-h'. This value defaults to '1' second.
Specify the interface to transmit from, if the machine has multiple interfaces.
Specify 802.1Q TCI (VLAN ID/CFI/priority combination). This feature is EXPERIMENTAL.
Verbose injection mode. Displays each packet you inject. It also has the same effect as in capture mode while used with the '-h' option.
This option defines the payload portion of the header. Hex payload should be prefixed with '0x' with each value separated by a whitespace. An ASCII example: -p 'hello, this is my packet'. A Hex example: -p '0x 70 61 63 6B 69 74'.
Specify the number of seconds to wait between packet bursts. This value defaults to '1' second.
Specify the size of the packet(s) to inject. The maximum value is 65535.

IP HEADER OPTIONS

This section documents the IP header command-line options.

The IP address the packet will appear to come from. If unspecified, packit will default to the IP address of the lowest numbered device in the 'up' state, excluding loopback.
Use a random source IP address.
The IP address of the machine you would like to contact.
Use a random destination IP address.
TOS values are typically in hexadecimal format, however, packit only accepts TOS values as integers. Below are the 4 valid TOS bit values:
  • Minimize delay: 16 (0x10)
  • Maximize throughput: 8 (0x08)
  • Maximize reliability: 4 (0x04)
  • Minimize monetary cost: 2 (0x02)
The ID number is used to identify each datagram sent by a host. It generally increments by one with each datagram sent. This value is random by default.
The TTL value defines the upper limit on the number of devices through which the datagram may pass to reach it's destination. The default value is 128.
Specify the IP protocol associated with this packet (RAWIP only). The default value is 255.

TCP HEADER OPTIONS

This section documents the TCP header command-line options.

The port from which our source address is communicating from. This value is random by default.
The port on the destination we would like to communicate on. In inject mode this value is 0 by default while in trace mode this value is random by default. You may also specify a range of addresses in the format: -D 1:1024.
Do not fragment this packet.
There are 6 TCP header flag bits. They can be used in combination with one another and are specified using the following identifiers:
  • S : SYN (Synchronization sequence number)
  • F : FIN (Sender is finished)
  • A : ACK (Acknowledgement number is valid)
  • P : PSH (Receiver should push this data to the remote host)
  • U : URG (The urgent pointer is valid)
  • R : RST (Reset this connection)

As an example, to set the SYN and FIN bits use the following: -F SF

The sequence number is a 32-bit unsigned (positive) number used to identify the byte in a stream of data from the sending TCP to the receiving TCP that the first byte of data represents.
The acknowledgement (ack) number defines the next sequence number that the sender of the ack expects to see. It is typically the sequence number + 1 during valid TCP communication. It is a 32-bit unsigned (positive) number.
The window size provides flow control. It is a 16-bit number that defines how many bytes the receiver is willing to accept. The default value is 1500.
In valid TCP communication, the urgent pointer is only useful if the URG flag is set. Used with the sequence number, it points to the last byte of urgent data.

UDP HEADER OPTIONS

This section documents the UDP header command-line options. UDP is the default IP protocol for TRACE mode.

The port from which our source address is communicating from. This value is random by default.
The port on the destination we would like to communicate on. In inject mode this value is 0 by default while in trace mode this value is random by default. You may also specify a range of addresses in the format: -D 1:1024.

ICMP HEADER OPTIONS

This section documents the ICMP header command-line options.

Specify the ICMP type. See docs/ICMP.txt for details on types. On Debian systems this file can be found at /usr/share/doc/packit/ICMP.txt.
Specify the ICMP code. See docs/ICMP.txt for details on codes. On Debian systems this file can be found at /usr/share/doc/packit/ICMP.txt.

ICMP ECHO REQUEST AND ECHO REPLY OPTIONS

Define the 16-bit ICMP identification number. This value is random by default.
Define the 16-bit ICMP sequence number. This value is random by default.

ICMP UNREACHABLE OR REDIRECT OR TIME EXCEEDED OPTIONS

Define the gateway in which to redirect traffic to. This option is only used for ICMP redirects (type 5).
Define the source address of the original packet.
Define the source port of the original packet.
Define the destination address of the original packet.
Define the destination port of the original packet.
Define the Time To Live of the original packet. This option defaults to 128.
Define the IP ID of the original packet. This option defaults to random.
Define the Type of Service of the original packet. See the -o option for the possible values.
Define the protocol of the original packet. This option defaults to UDP.

MASK REQUEST AND MASK REPLY OPTIONS

Define the 16-bit ICMP identification number. This value is random by default.
Define the 16-bit ICMP sequence number. This value is random by default.
Define the address network mask. The default value for this option is 255.255.255.0.

TIMESTAMP REQUEST AND TIMESTAMP REPLY OPTIONS

Define the 16-bit ICMP identification number. This value is random by default.
Define the 16-bit ICMP sequence number. This value is random by default.
Define the 32-bit original timestamp. This value is 0 by default.
Define the 32-bit received timestamp. This value is 0 by default.
Define the 32-bit transmit timestamp. This value is 0 by default.

ARP AND RARP HEADER OPTIONS

This section documents the ARP/RARP header command-line options. These options have the ability to do the most damage with the least effort, especially on large cable and DSL networks. Use with caution.

Packit only supports ARP/RARP protocol addresses in IPv4 format

Define the ARP / RARP / IRARP operation type. The valid options are as follows:
  • 1 : ARP Request (Default for ARP packages)
  • 2 : ARP Reply
  • 3 : Reverse ARP Request (Default for RARP packages)
  • 4 : Reverse ARP Reply
  • 5 : Inverse ARP Request
  • 6 : Inverse ARP Reply
The IP address of the target host.
Use a random target host IP address.
The Ethernet (hardware) address of the target host.
Usage a random target host Ethernet address.
The IP address of the sender host.
Use a random sender host IP address.
The Ethernet (hardware) address of the sender host.
Usage a random sender host Ethernet address.

ETHERNET HEADER OPTIONS

This section documents the Ethernet header command-line options.

The Ethernet (hardware) address the packet will appear to come from. If not defined, the original Ethernet address will be used.
Use a random source Ethernet address. If you define this, you will most likely need to define the destination Ethernet header value as well. When using either -e or -E, you enable link level packet injection and the destination cannot be auto-defined while injecting in this manner.
The Ethernet (hardware) of the next routeable interface which the packet will cross while making it's way to the destination.
Use a random destination Ethernet address. The following two rules should be followed if you actually want the destination to receive the packets you're sending:
1.
If the destination exists beyond your default route (gateway), the destination Ethernet address should be set to the default routes Ethernet address. This can typically be found by using the arp(8) command.
2.
If the destination exists on your subnet, the destination Ethernet address should be set to its Ethernet address. This can typically be found by using the arp(8) command.

PACKET CAPTURE EXAMPLES

Print all TCP communications that doesn't revolve around SSH (port 22):



    # packit -m cap 'tcp and not port 22'
Print the start and end packets (the SYN and FIN packets) of each TCP conversation that involves a non-local host, don't resolve addresses and display hex/ascii dump of the packet: 



    # packit -m cap -nX 'tcp[tcpflags] & (tcp-syn|tcp-fin) != 0 and not src and dst net localnet'
Write the first 10 ICMP packets captured to a file: 



    # packit -m cap -c 10 -w /tmp/mylog 'icmp'

PACKET INJECTION EXAMPLES

Inject 10 ICMP type 8 (echo request) packets from host '3.1.33.7' to host '192.168.0.1' and watch for a response:



    # packit -t icmp -s 3.1.33.7 -d 192.168.0.1 -c 10 -h
Inject an ICMP type 18 (mask reply) packet with an ICMP id of 211 and an address mask of 255.255.255.0: 



    # packit -t icmp -K 18 -d 127.0.0.1 -N 211 -G 255.255.255.0
Inject 5 TCP packets from random hosts to 'www.example.com' with the SYN flag set, a window size of 666, a random source Ethernet address, a destination Ethernet address of 00:53:00:0f:00:0d, with a payload of "HI JOHN", displaying each packet injected. 



    # packit -sR -d www.example.com -F S -c 5 -W 666 -eR -E 00:53:00:0f:00:0d -p 'HI JOHN' -v
or simplifying the MAC address: 



    # packit -sR -d www.example.com -F S -c 5 -W 666 -eR -E 0:53:0:f:00:d -p 'HI JOHN' -v
Inject a total of 1000 TCP packets in 20 packet per second bursts from 192.168.0.1 on port 403 to 192.168.0.20 on port 80 with the SYN and RST flags set, a sequence number of 12345678910 and a source Ethernet address of 0:0:0:0:0:0: 



    # packit -s 192.168.0.1 -d 192.168.0.20 -S 403 -D 80 -F SR -q 12345678910 -c 1000 -b 20 -e 0:0:0:0:0:0
Inject a TCP packets from 10.22.41.6 to 172.16.1.3 on ports ranging from 1-1024 with the SYN flag set and display each packet we send: 



    # packit -s 10.22.41.6 -d 172.16.1.3 -D 1-1024 -F S -v
Inject a broadcast ARP reply stating that 4.3.2.1 is at 00:53:00:01:02:03. Also, spoof the source Ethernet address for a little more authenticity and supply the payload in hex: 



    # packit -t arp -A 2 -x 4.3.2.1 -X 5:4:3:2:1:0 -e 00:53:00:01:02:03 -p '0x 70 61 63 6B 69 74'

TRACE ROUTE EXAMPLES

Appear as a DNS response by using a UDP source port of 53 (DNS):



    # packit -m trace -t UDP -d 192.168.2.35 -S 53
Appear as HTTP traffic by using TCP port 80: 



    # packit -m trace -t TCP -d www.google.com -S 80 -FS

BUGS

  • Due to limitations in some versions of *BSD, specifying arbitrary Ethernet and/or ARP header data may not be supported.
  • ARP capture data is incomplete.
  • Please send bug reports, questions, requests, fixes and pull requests to https://github.com/resurrecting-open-source-projects/packit/issues

SEE ALSO

arp(8), pcap(3), pcap-filter(7), tcpdump(1)

AUTHOR

The original author of packit is Darren Bounds. Currently, this project is maintained by volunteers.

The latest version of Packit can be found at https://github.com/resurrecting-open-source-projects/packit

04 Nov 2021 packit-1.8