tcptracer - Trace TCP established connections. Uses Linux eBPF/bcc. tcptracer [-h] [-v] [-p PID] [-N NETNS] This tool traces established TCP connections that open and close while tracing, and prints a line of output per connect, accept and close events. This includes the type of event, PID, IP addresses and ports. This tool works by using kernel dynamic tracing, and will need to be updated if the kernel implementation changes. Only established TCP connections are traced, so it is expected that the overhead of this tool is rather low. Since this uses BPF, only the root user can use this tool. CONFIG_BPF and bcc.

-h Print usage message.

-v Print full lines, with long event type names and network namespace numbers.

-p PID Trace this process ID only (filtered in-kernel).

-N NETNS Trace this network namespace only (filtered in-kernel).

Trace all TCP established connections: # tcptracer

Trace all TCP established connections with verbose lines: # tcptracer -v

Trace PID 181 only: # tcptracer -p 181

Trace connections in network namespace 4026531969 only: # tcptracer -N 4026531969

TYPE Type of event. In non-verbose mode: C for connect, A for accept, X for close.

PID Process ID

COMM Process name

IP IP address family (4 or 6)

SADDR Source IP address.

DADDR Destination IP address.

SPORT Source port.

DPORT Destination port.

NETNS Network namespace where the event originated.

This traces the kernel inet accept function, and the TCP connect, close, and set state functions. However, it only prints information for connections that are established, so it shouldn't have a huge overhead. As always, test and understand this tools overhead for your types of workloads before production use. This is from bcc. https://github.com/iovisor/bcc

Also look in the bcc distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool.

Linux Unstable - in development. Iago López Galeiras tcpaccept(8), tcpconnect(8), tcptop(8), tcplife(8)