# Cis Ubuntu1604 V200 3 5 3 1 2

> Ensure nftables is not installed with iptables

- Skill: `cyberstrikeus/cis-ubuntu1604-v200-3-5-3-1-2` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu1604-v200-3-5-3-1-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu1604-v200-3-5-3-1-2/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/cis-ubuntu1604-v200-3-5-3-1-2

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# CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - Control 3.5.3.1.2

## Profile

- **Level:** Level 1 - Server, Level 1 - Workstation
- **Assessment Status:** Automated

## Description

nftables is a subsystem of the Linux kernel providing filtering and classification of network packets/datagrams/frames and is the successor to iptables.

## Rationale

Running both iptables and nftables may lead to conflict.

## Audit Procedure

### Command Line

Run the following command to verify that nftables is not installed:

```bash
dpkg -s nftables
```

## Expected Result

```
dpkg-query: package 'nftables' is not installed
```

## Remediation

### Command Line

Run the following command to remove nftables:

```bash
apt purge nftables
```

## References

None

## CIS Controls

Version 7

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.