analyzing-network-flow-data-with-netflow

analyzing-network-flow-data-with-netflow is a skill for Claude Code, Codex from autohandai/community-skills. It costs 76 tokens per session (347 once invoked), scanned A, original, Apache-2.0.

A guide to reading NetFlow v9 and IPFIX records, which summarize network connections rather than storing every packet. It uses Python to find unusual traffic patterns in those records.

In plain words
What is it for?
Use it to collect and parse flow data, measure traffic against a baseline, and report possible port scans, unusual outbound transfers, periodic command-and-control connections, or volume spikes.
Why use it?
Large networks produce too much traffic to inspect packet by packet. Flow records make it easier to spot scanning, data theft, malware command traffic, and sudden traffic increases.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to collect and parse flow data, measure traffic against a baseline, and report possible port scans, unusual outbound transfers, periodic command-and-control connections, or volume spikes.

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Install with agentmods
npx agentmods add skills/autohandai/community-skills/analyzing-network-flow-data-with-netflow
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add autohandai/community-skills --skill analyzing-network-flow-data-with-netflow
Clone the repo
git clone --depth 1 https://github.com/autohandai/community-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for analyzing-network-flow-data-with-netflow

README.md
[![agentmods](https://agentmods.dev/badge/skills/autohandai/community-skills/analyzing-network-flow-data-with-netflow/github.svg)](https://agentmods.dev/skills/autohandai/community-skills/analyzing-network-flow-data-with-netflow)
Your own site
<a href="https://agentmods.dev/skills/autohandai/community-skills/analyzing-network-flow-data-with-netflow"><img src="https://agentmods.dev/badge/skills/autohandai/community-skills/analyzing-network-flow-data-with-netflow/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for analyzing-network-flow-data-with-netflow

Your own site · 80×15
<a href="https://agentmods.dev/skills/autohandai/community-skills/analyzing-network-flow-data-with-netflow"><img src="https://agentmods.dev/badge/skills/autohandai/community-skills/analyzing-network-flow-data-with-netflow.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 76 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 347 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00076 $0.00347
Opus 5 $0.00038 $0.00173
Sonnet 5 $0.00015 $0.00069
Haiku 4.5 $0.00008 $0.00035

Measured 11d ago against content hash b165cdbf5ec8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

analyzing-network-flow-data-with-netflow scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/agent.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

analyzing-network-flow-data-with-netflow/SKILL.md · 41 lines

What it actually says

Instructions

  1. Install dependencies: pip install netflow
  2. Collect NetFlow/IPFIX data from routers or use the built-in collector: python -m netflow.collector -p 9995
  3. Parse captured flow data using netflow.parse_packet().
  4. Analyze flows for:
    • Port scanning: single source to many destinations on same port
    • Data exfiltration: high byte-count outbound flows to unusual destinations
    • C2 beaconing: periodic connections with consistent intervals
    • Volumetric anomalies: traffic spikes beyond baseline thresholds
  5. Generate a prioritized findings report.
python scripts/agent.py --flow-file captured_flows.json --output netflow_report.json

Examples

Parse NetFlow v9 Packet

import netflow
data, _ = netflow.parse_packet(raw_bytes, templates={})
for flow in data.flows:
    print(flow.IPV4_SRC_ADDR, flow.IPV4_DST_ADDR, flow.IN_BYTES)
Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 11d ago First seen · 41 lines · 76 tokens per session scan A b165cdbf5ec8

Subscribe to this mod's changes

analyzing-network-flow-data-with-netflow is a skill published in the GitHub repository autohandai/community-skills (11 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 76 tokens to every session and 347 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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