1DERRICK(1) User Manual DERRICK(1)
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6 derrick -- a simple network stream recorder
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9 derrick [-mvVh] [-i interface] [-r file] [-f expression] [-l file] [-b
10 bytes] [-t lines]
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13 derrick is a simple tool for recording data streams of TCP and UDP
14 traffic. It shares similarities with other network recorders, such as
15 tcpflow and wireshark, where it is more advanced than the first and
16 clearly inferior to the latter.
17 derrick has been specifically designed to monitor application-layer
19 communication. In contrast to other tools the application data is
20 logged in a line-based text format. Common UNIX tools, such as grep,
21 sed & awk, can be directly applied. Even replay of recorded
22 communication is straight forward using netcat.
23 derrick supports on-the-fly compression and rotation of log files.
25 Payloads of TCP sessions are re-assembled using libnids and can be
26 merged or truncated. UDP payloads are logged as-is. Details of lower
27 network layers are omitted.
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30 derrick outputs the monitored network traffic in a line-based text
31 format, where each line corresponds to one recorded TCP or UDP payload.
32 Note that TCP payloads are re-assembled and thus not necessary match
33 the corresponding TCP datagrams.
34 Each line of the output has the following format:
36 <TIME> <FLAG> <SRC> <DST> <PAYLOAD>
38 The different fields of the output are defined as follows
40 <TIME> This field specifies the time at which the payload has been
42 monitored. The time is given as standard UNIX time and
43 encoded as a floating-point number of seconds.
44 <FLAG> This field indicates the type of payload that has been
46 recorded. U refers to a UDP payload and T refers to a TCP
47 payload. Additionally, the beginning and end of TCP streams
48 are marked by T+ and T-, respectively.
49 <SRC> This field specifies the source of the payload. It is a tuple
51 of an IP address and a port number in form of IP:PORT.
52 <DST> This field specifies the destination of the payload. It is a
54 tuple of an IP address and a port number in form of IP:PORT.
55 <PAYLOAD> The last field is the monitored payload. Non-printable
57 characters are escaped using standard URI encoding. Each non-
58 printable characters is replaced by %XX where XX is the
59 character's hexadecimal ASCII number.
60 An example output of derrick looks as follows
62 05.80 T 10.100.163.103:58445 91.198.174.233:80 GET /index.html ...
64 The line shows a TCP payload recorded at time 05.80, that is, 5.8
66 seconds after new year's eve of 1970 ;). The payload is directed to
67 port 80 (HTTP) and shows the beginning of a typical HTTP GET request.
68 Note that whitespaces are not escaped in the payload and thus each line
69 may seemingly have more than 5 fields. However, starting from the 5th
70 field all following white-spaces are part of the payload.
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73 derrick supports the following command-line options which can be used
74 to control the recording of network traffic.
75 -i interface Record network traffic from this interface. On Linux
77 systems with 2.2 or later kernels, an interface argument
78 of "any" can be used to capture packets from all
79 interfaces.
80 -r file Read network traffic from a dump file in pcap format.
82 Dump files can be created using tcpdump.
83 -f expression Filter network traffic using a filter expression. Only
85 packets that match the expression will be recorded.
86 Consult the man page of tcpdump for a description of
87 filter expressions.
88 -l file Write output to a compressed log file instead of stdout.
90 This option can be used when derrick runs in the
91 background. The log file will be rotated if a certain
92 number of lines have been logged, see -t.
93 -b bytes Record only the first bytes of each TCP stream. The
95 number of bytes is computed from incoming and outgoing
96 TCP payloads.
97 -m Merge consecutive TCP payloads in the same direction.
99 This options comes handy if protocol messages are split
100 over multiple TCP payloads.
101 -t lines Rotate the log file after the given number of lines.
103 -v Increase the verbosity of derrick during recording.
105 -h Print a brief help screen.
107 -V Print a version and copyright string.
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111 Copyright (c) 2011-2012 Konrad Rieck (konrad@mlsec.org)
112 Derrick is licensed under the new BSD License. See the file COPYING in
114 the source distribution for more information.
115derrick 0.3 2023-07-19 DERRICK(1)