# CIS Ubuntu 14.04 LTS - 3.4.3 Ensure /etc/hosts.deny is configured

> Verify that /etc/hosts.deny is configured to deny all unauthorized network access

- Skill: `cyberstrikeus/cis-ubuntu-14-04-lts-3-4-3-ensure-etc-hosts-deny-is-configur` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu-14-04-lts-3-4-3-ensure-etc-hosts-deny-is-configur`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu-14-04-lts-3-4-3-ensure-etc-hosts-deny-is-configur/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-ubuntu-14-04-lts-3-4-3-ensure-etc-hosts-deny-is-configur

---


# 3.4.3 Ensure /etc/hosts.deny is configured (Scored)

## Profile Applicability

- Level 1 - Server
- Level 1 - Workstation

## Description

The `/etc/hosts.deny` file specifies which IP addresses are **not** permitted to connect to the host. It is intended to be used in conjunction with the `/etc/hosts.allow` file.

## Rationale

The `/etc/hosts.deny` file serves as a failsafe so that any host not specified in `/etc/hosts.allow` is denied access to the system.

## Audit Procedure

Run the following command and verify the contents of the `/etc/hosts.deny` file:

```bash
cat /etc/hosts.deny
```

## Expected Result

```
ALL: ALL
```

## Remediation

Run the following command to create `/etc/hosts.deny`:

```bash
echo "ALL: ALL" >> /etc/hosts.deny
```

## Default Value

Contents of `/etc/hosts.deny` file may include additional options depending on your network configuration.

## References

- CIS Controls: 9.2 - Leverage Host-based Firewalls

## Profile

- Level 1 - Server
- Level 1 - Workstation