# Cis GCP Cos 3.3.3

> Ensure iptables is installed

- Skill: `cyberstrikeus/cis-gcp-cos-3-3-3` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-gcp-cos-3-3-3`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-gcp-cos-3-3-3/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/cis-gcp-cos-3-3-3

---


# 3.3.3 Ensure iptables is installed (Automated)

## Description

`iptables` allows configuration of the IPv4 and IPv6 tables in the linux kernel and the rules stored within them. Most firewall configuration utilities operate as a front end to `iptables`.

## Rationale

iptables is required for firewall management and configuration.

## Audit Procedure

Run the following command and verify iptables is installed:

```bash
grep '"name": "iptables"' /etc/cos-package-info.json
```

## Expected Result

```
"name": "iptables"
```

## Remediation

Update to an OS image that includes the iptables package.

## CIS Controls

| Controls Version | Control                                                                                                                                                                                                                                | IG 1 | IG 2 | IG 3 |
| ---------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---- | ---- | ---- |
| v8               | **4.4 Implement and Manage a Firewall on Servers** - Implement and manage a firewall on servers, where supported. Example implementations include a virtual firewall, operating system firewall, or a third-party firewall agent.      | x    | x    | x    |
| v7               | **9.4 Apply Host-based Firewalls or Port Filtering** - Apply host-based firewalls or port filtering tools on end systems, with a default-deny rule that drops all traffic except those services and ports that are explicitly allowed. | x    | x    | x    |

## Profile

- Level 1 - Server