Skip to content



NetFlowTCPBegin - An event derived from a base network raw event, originated from cgroup skb eBPF programs, specifically designed to monitor the initiation of TCP flows by analyzing IP and TCP headers data.


NetFlowTCPBegin leverages cgroup skb eBPF programs to capture raw network events at the kernel level, focusing on the TCP protocol's initiation phase.

This event parses IP and TCP headers, identifying the start of TCP communication flows based on SYN, ACK, and FIN flag statuses. By concentrating on these flags, NetFlowTCPBegin efficiently discerns the commencement of TCP connections, providing critical data for network monitoring and security analysis.


  1. connectionDirection (string): Classifies the connection as 'incoming' or 'outgoing', based on the packet's direction and SYN flag status.
  2. srcIP (string): The source IP address extracted directly from the IP header.
  3. dstIP (string): The destination IP address, ascertained from the IP header.
  4. srcPort (uint16): The source port, derived from the TCP header.
  5. dstPort (uint16): The destination port, obtained from the TCP header.
  6. srcDomains ([]string): Domain names related to the source IP, resolved through DNS cache.
  7. dstDomains ([]string): Domain names associated with the destination IP, also resolved via DNS cache.


Derived from cgroup skb eBPF Programs


The NetFlowTCPBegin event originates from cgroup skb eBPF programs, which capture and process raw network packets at the kernel level. This sophisticated capture mechanism is specifically tailored for dissecting and analyzing TCP traffic, particularly at the initiation stage of TCP connections.


The event's primary goal is to provide in-depth visibility into the initiation of TCP connections. By focusing on SYN/ACK/FIN flags within TCP headers, NetFlowTCPBegin offers an efficient and accurate method for identifying the start of TCP communication flows, crucial for network security and performance analysis.

Example Use Case

Network administrators and security professionals can utilize NetFlowTCPBegin to track the initiation of TCP connections, aiding in the early detection of unusual traffic patterns or unauthorized communication attempts. This information is vital for maintaining network integrity and preempting potential security breaches.


Although NetFlowTCPBegin is optimized for low overhead, its efficiency depends on the network traffic volume and the complexity of the TCP flows being monitored. Proper management and analysis of the generated data are essential to maximize the benefits of this event without impacting system performance.

  • net_tcp_connect - similar event, based on the security_socket_connect calls.
  • security_socket_connect

This document was automatically generated by OpenAI and reviewed by a Human.