TCP Connection

The TCP Connection plugin turns IO Ninja into a raw TCP terminal, allowing you to connect to network nodes, send custom packets, and analyze responses. It lets you prepare packets in binary mode with a hex editor and provides detailed logging and transmission capabilities. You can also configure aspects of the TCP socket, such as the local interface, port, Nagle’s algorithm, and how connections are closed. This makes it a practical tool for exploring network behavior and testing TCP communication.

Capabilities

Recommended

com.ioninja.script

Enables the script pane and packet templates.

Optional

org.jancy.io.ip6

Required for establishing IPv6 connections.

Basic Setup

1. In IO Ninja, click the “New Session” dropdown and select “TCP Connection”.

2. Set your target address/port and click “Connect”.

3. Use the “Transmit” pane to craft a custom packet, and then press send.

4. Adjust settings as needed via the “Settings” button (see “Settings” section below for details).

Settings

Setting	Description	Default
Remote address	Remote address to connect to. Can be specified via IPv4 (127.0.0.1), IPv6 (::1), or a domain name (localhost). Remote address can be suffixed with the remote port after a colon, e.g. ioninja.com:443.
Remote port (default)	Remote port to connect to in cases when a port is not explicitly specified in Remote address.	80
Reconnect	Attempt to reconnect when connection is dropped by the remote node.	False
Reconnect timeout	The delay between reconnect attempts.	3000
Use local address	Bind socket to the specified local address.	False
Adapter	Local network adapter to bind to. Pick one from the list of installed network adapters (or bind to all installed IP4 or all IP6 adapters at once).	Auto
Local port	Local port to bind to. Setting this to 0 auto-selects an available port.	8080
Reuse address	Allow multiple sockets to share the same local address. Maps to the SO_REUSEADDR socket option. Please note, the support and details of implementation for this option are highly platform-specific.	False
TCP Nagle algorithm	Delay transmission to reduce the number of small TCP packets. Maps to the TCP_NODELAY socket option.	False
TCP reset	Drop TCP connections abruptly with a TCP RST packet. Maps to the SO_LINGER socket option.	False
TCP keep-alives	Detect connection loss with TCP keep-alive probes. Maps to the TCP_KEEPALIVE socket option.	False
Read parallelism (Windows-only)	Maximum number of read requests to issue in parallel. Having more than one pending read at a time helps with increasing read throughput when incoming data arrives in rapid streams (after filling one user buffer, the kernel can immediately switch to the next one without any waiting). Increasing this number beyond 4 usually won’t yield any extra performance gains.	4
Read block size (B)	The size of each individual read block submitted to the underlying transport.	4KB
RX buffer size (B)	The full size of the incoming data (RX) buffer. Affects read throughput.	16KB
TX buffer size (B)	The full size of the outbound data (TX) buffer. Affects write throughput.	16KB
Keep read block size	Don’t merge read blocks in RX buffer. Incoming data blocks coming in quick succession can be merged together so that IO Ninja writes them to log as a whole. When this option is set to True, blocks are written to the log without merging, i.e., exactly as they are received from the underlying transport.	False
Keep write block size	Don’t merge write blocks in TX buffer. Outbound data blocks sent in quick succession can be merged together before submission to the underlying transport. When this option is set to True, blocks are submitted to the transport without merging, i.e., exactly as they are sent by the Transmit or Script panes.	False
RX buffer full notifications	Toggle warnings in log about the incoming data (RX) buffer getting full.	False

Note

An example of an adapter dropdown on a typical Windows laptop is shown below:

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See Also

• TCP Connection Product Page