bcc-tcpconnect(8)

1tcpconnect(8)               System Manager's Manual              tcpconnect(8)
2
3
4

NAME

6       tcpconnect  -  Trace  TCP  active  connections  (connect()). Uses Linux
7       eBPF/bcc.
8

SYNOPSIS

10       tcpconnect [-h] [-t] [-x] [-p PID] [-P PORT]
11

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.
16
17       All connection attempts are traced, even if they ultimately fail.
18
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.
22
23       Since this uses BPF, only the root user can use this tool.
24

REQUIREMENTS

26       CONFIG_BPF and bcc.
27

OPTIONS

29       -h     Print usage message.
30
31       -t     Include a timestamp column.
32
33       -p PID Trace this process ID only (filtered in-kernel).
34
35       -P PORT
36              Comma-separated list of destination ports to trace (filtered in-
37              kernel).
38

EXAMPLES

40       Trace all active TCP connections:
41              # tcpconnect
42
43       Trace all TCP connects, and include timestamps:
44              # tcpconnect -t
45
46       Trace PID 181 only:
47              # tcpconnect -p 181
48
49       Trace ports 80 and 81 only:
50              # tcpconnect -P 80,81
51

FIELDS

53       TIME(s)
54              Time of the call, in seconds.
55
56       PID    Process ID
57
58       COMM   Process name
59
60       IP     IP address family (4 or 6)
61
62       SADDR  Source IP address.
63
64       DADDR  Destination IP address.
65
66       DPORT  Destination port
67

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.
74

SOURCE

76       This is from bcc.
77
78              https://github.com/iovisor/bcc
79
80       Also  look  in  the bcc distribution for a companion _examples.txt file
81       containing example usage, output, and commentary for this tool.
82

OS

84       Linux
85

STABILITY

87       Unstable - in development.
88

AUTHOR

90       Brendan Gregg
91