routeros-mac-telnet

routeros-mac-telnet is a skill for Claude Code, Codex from tikoci/routeros-skills. It costs 141 tokens per session (6,820 once invoked), scanned A, original, MIT.

A technical guide to MAC-Telnet, a MikroTik protocol for opening a RouterOS terminal by device MAC address instead of an IP address.

In plain words
What is it for?
Use it to implement or debug MAC-Telnet clients and servers, parse packets, connect to devices by MAC address, and handle MD5 or MTWEI authentication.
Why use it?
It provides a way to reach a device that has no working or reachable IP address, while explaining its packet format and authentication methods.

Skill for Claude CodeCodex

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

Good fit Use it to implement or debug MAC-Telnet clients and servers, parse packets, connect to devices by MAC address, and handle MD5 or MTWEI authentication.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/tikoci/routeros-skills/routeros-mac-telnet
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-mac-telnet
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-mac-telnet

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/tikoci/routeros-skills/routeros-mac-telnet"><img src="https://agentmods.dev/badge/skills/tikoci/routeros-skills/routeros-mac-telnet.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 141 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 6,820 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 $0.00141 $0.06820
Opus 5 $0.00071 $0.03410
Sonnet 5 $0.00028 $0.01364
Haiku 4.5 $0.00014 $0.00682

Measured 11d ago against content hash 24271252584a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

routeros-mac-telnet 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.

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-mac-telnet/SKILL.md · 461 lines

How it starts

The opening of the file, as written. The whole thing — 461 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MAC-Telnet — MikroTik Layer-2 Terminal Protocol

MAC-Telnet lets you open an interactive RouterOS terminal (or run commands) addressing a device by its MAC address — you do not need to know or route to the target's IP. It works across a Layer-2 broadcast domain even when the target has no IP, a wrong IP, or an IP you cannot route to, which is why WISPs and provisioning tools rely on it. WinBox's "MAC Telnet" and the tools/mac-telnet CLI use this protocol family.

Why This Matters for Agents

  • It is the only way to get a shell on a freshly-unboxed or misconfigured RouterOS device that has no reachable IP.
  • The protocol carries its own 6+6-byte source/destination MAC addressing inside every packet, independent of the outer UDP/L2 delivery. This trips up implementers who assume normal UDP semantics.
  • Authentication has two incompatible modes — classic MD5 and modern MTWEI (EC-SRP over Curve25519). Current RouterOS 7.x defaults to MTWEI; getting the mode-detection wrong is the single most common failure.
  • It is simple enough to implement from scratch for the MD5 path; MTWEI needs an elliptic-curve library.

Protocol Basics

Property Value
Transport UDP
Port 20561 (server listens; client may use an ephemeral or matching source port)
Addressing In-packet 6-byte src + 6-byte dst MAC (the real addressing); outer UDP/IP is just transport
Delivery Layer-2 — broadcast or unicast Ethernet frame to the target MAC; does not cross routers
Reliability Application-level: byte-counter ACKs + timed retransmission (UDP gives none)
Session Stateful handshake → authenticated → raw terminal stream → teardown
Auth MD5 (legacy) or MTWEI / EC-SRP (current RouterOS 7.x default)
Max packet 1500 bytes (MT_PACKET_LEN)

MAC-Telnet (UDP 20561) is a sibling of MNDP (UDP 5678) from the same MikroTik L2 toolset: MNDP discovers the device and its MAC; MAC-Telnet then connects to that MAC. See the routeros-mndp skill for discovery. They are otherwise independent wire formats — MNDP is a one-shot TLV announcement with no session, auth, control-block magic, or 00 15 client-type.

Read the full file on GitHub · 461 lines

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 · 461 lines · 141 tokens per session scan A 24271252584a

Subscribe to this mod's changes

routeros-mac-telnet is a skill published in the GitHub repository tikoci/routeros-skills (59 stars, last pushed 1mo ago), licensed MIT. It adds 141 tokens to every session and 6,820 once invoked, about $0.0007 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.