# Source: https://docs.datadoghq.com/security/default_rules/gdz-mkr-i6f.md

---
title: The UTS namespace should not be shared with the host
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > OOTB Rules > The UTS namespace should not be shared
  with the host
---

# The UTS namespace should not be shared with the host
Classification:complianceFramework:cis-dockerControl:5.20 
## Description{% #description %}

UTS namespaces provide isolation between two system identifiers: the hostname and the NIS domain name. It is used to set the hostname and the domain which are visible to running processes in that namespace. Processes running within containers do not typically require to know either the hostname or the domain name. The UTS namespace should therefore not be shared with the host.

## Rationale{% #rationale %}

Sharing the UTS namespace with the host provides full permission for each container to change the hostname of the host. This is not in line with good security practice and should not be permitted.

## Audit{% #audit %}

Run this command: `docker ps --quiet --all | xargs docker inspect --format '{{ .Id }}: UTSMode={{ .HostConfig.UTSMode }}'`

If this command returns `host`, it means the host UTS namespace is shared with the container and this recommendation is non-compliant. If the above command returns nothing, then the host's UTS namespace is not shared. This recommendation is then compliant.

## Remediation{% #remediation %}

You should not start a container with the `--uts=host` argument. For example, do not start a container using the command `docker run --rm --interactive --tty --uts=host rhel7.2`

## Impact{% #impact %}

None

## Default value{% #default-value %}

By default, all containers have the UTS namespace enabled and the host UTS namespace is not shared with any containers.

## References{% #references %}

1. [https://docs.docker.com/engine/reference/run/#uts-settings-uts](https://docs.docker.com/engine/reference/run/#uts-settings-uts)
1. [http://man7.org/linux/man-pages/man7/namespaces.7.html](http://man7.org/linux/man-pages/man7/namespaces.7.html)

## CIS controls{% #cis-controls %}

Version 6

18 Application Software Security Application Software Security