1tcpconnect(8)               System Manager's Manual              tcpconnect(8)
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NAME

6       tcpconnect  -  Trace  TCP  active  connections  (connect()). Uses Linux
7       eBPF/bcc.
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SYNOPSIS

10       tcpconnect [-h] [-t] [-x] [-p PID] [-P PORT]
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DESCRIPTION

13       This tool traces active TCP connections (eg, via a  connect()  syscall;
14       accept() are passive connections). This can be useful for general trou‐
15       bleshooting to see what connections are initiated by the local server.
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17       All connection attempts are traced, even if they ultimately fail.
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19       This works by tracing the kernel tcp_v4_connect() and  tcp_v6_connect()
20       functions  using  dynamic  tracing, and will need updating to match any
21       changes to these functions.
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23       Since this uses BPF, only the root user can use this tool.
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REQUIREMENTS

26       CONFIG_BPF and bcc.
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OPTIONS

29       -h     Print usage message.
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31       -t     Include a timestamp column.
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33       -p PID Trace this process ID only (filtered in-kernel).
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35       -P PORT
36              Comma-separated list of destination ports to trace (filtered in-
37              kernel).
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EXAMPLES

40       Trace all active TCP connections:
41              # tcpconnect
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43       Trace all TCP connects, and include timestamps:
44              # tcpconnect -t
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46       Trace PID 181 only:
47              # tcpconnect -p 181
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49       Trace ports 80 and 81 only:
50              # tcpconnect -P 80,81
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FIELDS

53       TIME(s)
54              Time of the call, in seconds.
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56       PID    Process ID
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58       COMM   Process name
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60       IP     IP address family (4 or 6)
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62       SADDR  Source IP address.
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64       DADDR  Destination IP address.
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66       DPORT  Destination port
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OVERHEAD

69       This  traces  the  kernel tcp_v[46]_connect functions and prints output
70       for each event. As the rate of this is generally expected to be low  (<
71       1000/s), the overhead is also expected to be negligible. If you have an
72       application that is calling a high rate of connects()s, such as a proxy
73       server, then test and understand this overhead before use.
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SOURCE

76       This is from bcc.
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78              https://github.com/iovisor/bcc
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80       Also  look  in  the bcc distribution for a companion _examples.txt file
81       containing example usage, output, and commentary for this tool.
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OS

84       Linux
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STABILITY

87       Unstable - in development.
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AUTHOR

90       Brendan Gregg
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SEE ALSO

93       tcpaccept(8), funccount(8), tcpdump(8)
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97USER COMMANDS                     2015-08-25                     tcpconnect(8)
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