routeros-firewall

routeros-firewall is a skill for Claude Code, Codex from tikoci/routeros-skills. It costs 92 tokens per session (1,884 once invoked), scanned A, original, MIT.

A guide to the MikroTik RouterOS firewall, which controls, translates, marks, and groups network traffic using ordered rules.

In plain words
What is it for?
Use it to write filter, NAT, and mangle rules, manage address lists, redirect DNS, forward ports, and create repeatable firewall scripts.
Why use it?
It clarifies that rules are checked from top to bottom and helps prevent incorrect ordering, ineffective drops, and unnecessarily repeated rules.

Skill for Claude CodeCodex

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

Good fit Use it to write filter, NAT, and mangle rules, manage address lists, redirect DNS, forward ports, and create repeatable firewall scripts.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/tikoci/routeros-skills/routeros-firewall
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 tikoci/routeros-skills --skill routeros-firewall
Clone the repo
git clone --depth 1 https://github.com/tikoci/routeros-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 routeros-firewall

README.md
[![agentmods](https://agentmods.dev/badge/skills/tikoci/routeros-skills/routeros-firewall/github.svg)](https://agentmods.dev/skills/tikoci/routeros-skills/routeros-firewall)
Your own site
<a href="https://agentmods.dev/skills/tikoci/routeros-skills/routeros-firewall"><img src="https://agentmods.dev/badge/skills/tikoci/routeros-skills/routeros-firewall/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 routeros-firewall

Your own site · 80×15
<a href="https://agentmods.dev/skills/tikoci/routeros-skills/routeros-firewall"><img src="https://agentmods.dev/badge/skills/tikoci/routeros-skills/routeros-firewall.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 92 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,884 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00092 $0.01884
Opus 5 $0.00046 $0.00942
Sonnet 5 $0.00018 $0.00377
Haiku 4.5 $0.00009 $0.00188

Measured 12d ago against content hash 4ada00c81fa0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

routeros-firewall 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 12d ago.

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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

routeros-firewall/SKILL.md · 160 lines

How it starts

The opening of the file, as written. The whole thing — 160 lines — stays where its author put it; the contents beside it link to each section on GitHub.

RouterOS Firewall

Rule Ordering — Sequential, Not Priority-Based

Rules are evaluated top-to-bottom — first match wins. This is the biggest source of iptables confusion.

  • place-before=0 inserts at the top; default add appends at the bottom
  • An action=accept rule must appear BEFORE any action=drop for the same traffic
  • Non-terminal actions do NOT stop evaluation: action=add-src-to-address-list, action=add-dst-to-address-list, action=log, and any rule with passthrough=yes continue to the next rule. A drop rule below an add-src-to-address-list will still fire.
# WRONG — drop fires before accept can match
/ip/firewall/filter/add chain=input action=drop
/ip/firewall/filter/add chain=input src-address=10.0.0.1 action=accept

# CORRECT — accept first, drop catches the rest
/ip/firewall/filter/add chain=input src-address=10.0.0.1 action=accept place-before=0
/ip/firewall/filter/add chain=input action=drop

Address-Lists as Dynamic Selectors

LLMs rarely suggest this pattern — they write one rule per IP address instead. Address-lists scale to hundreds of IPs with a single firewall rule.

# Build the list (static or dynamic with auto-expiry)
/ip/firewall/address-list/add list=trusted-mgmt address=192.168.1.0/24
/ip/firewall/address-list/add list=trusted-mgmt address=10.0.0.5 timeout=1h

# One rule handles all list members
/ip/firewall/filter/add chain=input src-address-list=trusted-mgmt action=accept \
  comment="myapp-accept-mgmt"

Dynamic entries with timeout= expire automatically — the primary pattern for DoS blacklists.

Interface-Lists as Rule Selectors

in-interface-list= / out-interface-list= — powerful RouterOS pattern LLMs never propose. Eliminates duplicate rules when multiple interfaces serve the same role.

# Define the group once
/interface/list/add name=WAN
/interface/list/member/add list=WAN interface=ether1
/interface/list/member/add list=WAN interface=pppoe-out1

# One rule applies to all WAN interfaces
/ip/firewall/filter/add chain=input in-interface-list=WAN action=drop \
  comment="myapp-drop-all-wan"

Read the full file on GitHub · 160 lines

Files

What ships with it

2 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. 12d ago First seen · 160 lines · 92 tokens per session scan A 4ada00c81fa0

Subscribe to this mod's changes

routeros-firewall is a skill published in the GitHub repository tikoci/routeros-skills (59 stars, last pushed 1mo ago), licensed MIT. It adds 92 tokens to every session and 1,884 once invoked, about $0.0005 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 2026-08-30.