What is unifi-dns-triage?

A troubleshooting guide for deciding whether a UniFi problem is caused by DNS, the system that turns names such as google.com into network addresses, or by general connectivity.

Use it when some sites fail, hostnames do not resolve, internal names stop working, or DNS settings changed. It tests connectivity, compares DNS resolvers, and checks network and device configuration.

It separates name-resolution failures from internet or routing failures, which require different fixes.

unifi-dns-triage — Skill for Claude Code by mikeholownych/unifi-mcp

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 mikeholownych/unifi-mcp --skill unifi-dns-triage

Clone the repo

git clone --depth 1 https://github.com/mikeholownych/unifi-mcp

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/mikeholownych/unifi-mcp/unifi-dns-triage/github.svg)](https://agentmods.dev/skills/mikeholownych/unifi-mcp/unifi-dns-triage)

Your own site

<a href="https://agentmods.dev/skills/mikeholownych/unifi-mcp/unifi-dns-triage"><img src="https://agentmods.dev/badge/skills/mikeholownych/unifi-mcp/unifi-dns-triage/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/mikeholownych/unifi-mcp/unifi-dns-triage"><img src="https://agentmods.dev/badge/skills/mikeholownych/unifi-mcp/unifi-dns-triage.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 859 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.

Model	Per session	Once invoked
Fable 5.1	$0.00055	$0.00859
Opus 5.5	$0.00022	$0.00344
Sonnet 5.5	$0.00011	$0.00172
Haiku 4.5	$0.00006	$0.00086

Measured 2mo ago against content hash b8528399463e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

unifi-dns-triage 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 2mo 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.

skills/unifi-dns-triage/SKILL.md · 67 lines

How it starts

The opening of the file, as written. The whole thing — 67 lines — stays where its author put it; the contents beside it link to each section on GitHub.

UniFi DNS Triage

Separate name resolution failures from connectivity failures — they look identical to users ("the internet is broken") but have completely different fixes.

Step 0 — Version & context

get_sysinfo for Network version (facts verified on 10.x). Then get_networks — note each network's domain_name and topology.

The test ladder (run in order, stop at first break)

Have the user (or use your own knowledge of results) run:

ping 8.8.8.8 — works? → connectivity is FINE; this is DNS. Skip to 3. fails? → genuine connectivity issue → route to unifi-internet-down.
ping google.com — resolves? Public DNS works. fails with "could not be resolved" → name resolution broken. Continue.
nslookup google.com (uses DHCP-given resolver) vs nslookup google.com 8.8.8.8:
- Direct-to-8.8.8.8 works but default resolver fails → the configured internal resolver is dead or unreachable → step 4.
- Both fail → device-side (wrong DNS manually set, captive portal, VPN app).
Identify the resolver chain: get_networks (per-network domain_name), get_client_details on the affected device (which network/DNS it holds). On networks where an AD/domain exists (ad.holownych.com style), the resolvers are typically domain controllers — check those hosts are up (list_clients / get_device_details).

Controller-specific patterns (Network 9+/10 zone firewall)

Internal-DNS enforcement is commonly done by BLOCK rules on outbound tcp/udp 53 per zone (look for names like "external DNS block", "Block WORK External DNS" in get_firewall_policies). Consequences:
- Devices with hardcoded 8.8.8.8 silently fail to resolve → fix the device, not the firewall.
- DoH/DoT escape (443/853) is NOT blocked by port-53 rules — devices may resolve via encrypted DNS and bypass internal names entirely.
- Allow-rules to DNS-server zones are often scoped tcp_udp 53 ONLY — other DNS transports will fail while basic lookups work.
Split-horizon: internal names (*.ad.holownych.com) resolve ONLY via internal resolvers. "Works at office, fails at home" (or vice versa) is normal.
If ALL resolution dies house-wide but WAN is up: prime suspect is the DNS server zone being down or a changed zone-policy (verify with get_firewall_policies: are the "X to DNS Servers" allows still enabled?).

Read the full file on GitHub · 67 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.

2mo ago First seen · 67 lines · 55 tokens per session scan A b8528399463e

Subscribe to this mod's changes

unifi-dns-triage is a skill published in the GitHub repository mikeholownych/unifi-mcp (2 stars, last pushed 13d ago), licensed MIT. It adds 55 tokens to every session and 859 once invoked, about $0.0002 per session on Opus 5.5. 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.

Debugging Hardware and IoT

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