bcc-tcpconnect(8)

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] [-c] [-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       -c     Count connects per src ip and dest ip/port.
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35       -p PID Trace this process ID only (filtered in-kernel).
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37       -P PORT
38              Comma-separated list of destination ports to trace (filtered in-
39              kernel).
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EXAMPLES

42       -U     Include a UID column.
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44       -u UID Trace this UID only (filtered in-kernel).
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46       Trace all active TCP connections:
47              # tcpconnect
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49       Trace all TCP connects, and include timestamps:
50              # tcpconnect -t
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52       Trace PID 181 only:
53              # tcpconnect -p 181
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55       Trace ports 80 and 81 only:
56              # tcpconnect -P 80,81
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58       Trace all TCP connects, and include UID:
59              # tcpconnect -U
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61       Trace UID 1000 only:
62              # tcpconnect -u 1000
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64       Count connects per src ip and dest ip/port:
65              # tcpconnect -c
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FIELDS

68       TIME(s)
69              Time of the call, in seconds.
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71       UID    User ID
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73       PID    Process ID
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75       COMM   Process name
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77       IP     IP address family (4 or 6)
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79       SADDR  Source IP address.
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81       DADDR  Destination IP address.
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83       DPORT  Destination port
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85       CONNECTS
86              Accumulated active connections since start.
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OVERHEAD

89       This  traces  the  kernel tcp_v[46]_connect functions and prints output
90       for each event. As the rate of this is generally expected to be low  (<
91       1000/s), the overhead is also expected to be negligible. If you have an
92       application that is calling a high rate of connect()s, such as a  proxy
93       server, then test and understand this overhead before use.
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SOURCE

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

104       Linux
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STABILITY

107       Unstable - in development.
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AUTHOR

110       Brendan Gregg
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