What is configuring-firewalls?

Firewall configuration for DigitalOcean Droplets, which are cloud-hosted virtual servers. It defines which network connections are allowed or blocked.

Use it to secure servers, create application and database access rules, and apply network security policies.

It helps prevent unwanted access by allowing only the traffic a server needs, such as web requests or restricted SSH access.

configuring-firewalls — Skill for Claude Code by iamnolanhu

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 iamnolanhu/digitalocean-skills --skill configuring-firewalls

Clone the repo

git clone --depth 1 https://github.com/iamnolanhu/digitalocean-skills

Made for: Claude Code.

Or install digitalocean-skills, the plugin that ships this one along with the rest of its 9 skills, 6 commands, 3 agents, 1 hook.

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/iamnolanhu/digitalocean-skills/configuring-firewalls/github.svg)](https://agentmods.dev/skills/iamnolanhu/digitalocean-skills/configuring-firewalls)

Your own site

<a href="https://agentmods.dev/skills/iamnolanhu/digitalocean-skills/configuring-firewalls"><img src="https://agentmods.dev/badge/skills/iamnolanhu/digitalocean-skills/configuring-firewalls/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/iamnolanhu/digitalocean-skills/configuring-firewalls"><img src="https://agentmods.dev/badge/skills/iamnolanhu/digitalocean-skills/configuring-firewalls.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,386 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 1 finding. 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	$0.00048	$0.01386
Opus 5	$0.00024	$0.00693
Sonnet 5	$0.00010	$0.00277
Haiku 4.5	$0.00005	$0.00139

Measured 11d ago against content hash 31cf64ab5afc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

configuring-firewalls scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s -H "Authorization: Bearer $DIGITALOCEAN_API_TOKEN" \

skills/configuring-firewalls/SKILL.md · 196 lines

How it starts

The opening of the file, as written. The whole thing — 196 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Configuring Firewalls

Design and implement DigitalOcean Cloud Firewalls following defense-in-depth principles.

When to Use

Securing new or existing Droplets
Implementing least-privilege network access
Setting up security groups for applications
User mentions: "firewall", "security", "block", "allow port", "restrict access"

Core Principles

Deny by default - Only allow what's explicitly needed
Least privilege - Minimum access required for function
Defense in depth - Multiple layers of protection
Audit trail - Tag firewalls for tracking

Common Firewall Patterns

Pattern 1: Web Server

Inbound:
  - TCP 80 (HTTP) from 0.0.0.0/0
  - TCP 443 (HTTPS) from 0.0.0.0/0
  - TCP 22 (SSH) from <your-ip>/32

Outbound:
  - All traffic (for updates, external APIs)

Pattern 2: Application Server (Behind LB)

Inbound:
  - TCP 8080 from <load-balancer-ip>/32
  - TCP 22 from <bastion-ip>/32

Outbound:
  - TCP 5432 to <database-vpc-cidr>
  - TCP 443 to 0.0.0.0/0 (external APIs)

Pattern 3: Database Server

Inbound:
  - TCP 5432 (PostgreSQL) from <app-vpc-cidr>
  - TCP 22 from <bastion-ip>/32

Outbound:
  - TCP 443 to 0.0.0.0/0 (updates only)

Pattern 4: Bastion/Jump Host

Inbound:
  - TCP 22 from <office-ip>/32
  - TCP 22 from <vpn-cidr>

Outbound:
  - TCP 22 to <vpc-cidr>

The Process

1. Audit Current State

firewall-list
droplet-list (check which Droplets have firewalls)

2. Design Firewall

Questions to ask:

What service does this Droplet run?
Who/what needs to connect to it?
What does it need to connect to?
Is it public-facing or internal?

3. Create Firewall

firewall-create:
  Name: fw-<environment>-<service>
  InboundRules:
    - Protocol: tcp
      Ports: "443"
      Sources:
        Addresses: ["0.0.0.0/0", "::/0"]
    - Protocol: tcp
      Ports: "22"
      Sources:
        Addresses: ["<your-ip>/32"]
  OutboundRules:
    - Protocol: tcp
      Ports: "all"
      Destinations:
        Addresses: ["0.0.0.0/0", "::/0"]
  DropletIDs: [<droplet-id>]
  Tags: ["env:<environment>"]

Read the full file on GitHub · 196 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.

11d ago First seen · 196 lines · 48 tokens per session scan A 31cf64ab5afc

Subscribe to this mod's changes

configuring-firewalls is a skill published in the GitHub repository iamnolanhu/digitalocean-skills (4 stars, last pushed 7mo ago), licensed MIT. It adds 48 tokens to every session and 1,386 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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