# Cis Ubuntu1204 V110 7 1 1

> Disable IP Forwarding

- Skill: `cyberstrikeus/cis-ubuntu1204-v110-7-1-1` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-ubuntu1204-v110-7-1-1`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-ubuntu1204-v110-7-1-1/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-ubuntu1204-v110-7-1-1

---


# 7.1.1 Disable IP Forwarding (Scored)

## Profile Applicability

- Level 1

## Description

The `net.ipv4.ip_forward` flag is used to tell the server whether it can forward packets or not. If the server is not to be used as a router, set the flag to 0.

## Rationale

Setting the flag to 0 ensures that a server with multiple interfaces (for example, a hard proxy), will never be able to forward packets, and therefore, never serve as a router.

## Audit Procedure

### Using Command Line

Perform the following to determine if `net.ipv4.ip_forward` is enabled on the system.

```bash
/sbin/sysctl net.ipv4.ip_forward
```

## Expected Result

```
net.ipv4.ip_forward = 0
```

## Remediation

### Using Command Line

Set the `net.ipv4.ip_forward` parameter to 0 in `/etc/sysctl.conf`:

```bash
net.ipv4.ip_forward=0
```

Modify active kernel parameters to match:

```bash
/sbin/sysctl -w net.ipv4.ip_forward=0
/sbin/sysctl -w net.ipv4.route.flush=1
```

## Default Value

IP forwarding is disabled by default.

## References

- CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0

## Profile

Level 1 - Scored