---
myst:
  html_meta:
    description: Security concepts and best practices for Ubuntu Server including authentication, cryptography, VPNs, and system hardening strategies.
---

(explanation-security)=
# Security

There are many steps you can take to strengthen the security posture of your system. In this section you will find explanations of various concepts related to security.

## General configuration

* {ref}`Introduction to security <introduction-to-security>` for a high-level overview of security in Ubuntu
* {ref}`security-suggestions` provides general recommendations for any Ubuntu system, from straightforward setups to more advanced and complex systems

```{toctree}
:hidden:

intro-to/security
security/security_suggestions
```

## Authentication

* {ref}`Introduction to Kerberos <introduction-to-kerberos>`, the network authentication system
* {ref}`Introduction to SSSD <introduction-to-network-user-authentication-with-sssd>`, the collection of daemons that handle authentication from various network sources
* {ref}`About DNSSEC <dnssec>`, the security extension for the Domain Name System (DNS).

```{toctree}
:hidden:

intro-to/kerberos
intro-to/sssd
DNSSEC <dnssec/dnssec>
```

## Cryptography

* {ref}`Our cryptography section <explanation-cryptography>` explains in detail about the different cryptographic libraries and configurations you might encounter.
* {ref}`Certificates <certificates>` are issued, stored and signed by a Certificate Authority (CA) to create trusted connections.

```{toctree}
:hidden:

cryptography
Certificates <security/certificates>
```

## Virtual Private Network (VPN)

VPNs are commonly used to provide encrypted, secure access to a network. 

* {ref}`Introduction to WireGuard VPN <introduction-to-wireguard-vpn>`, a popular and modern VPN implementation
* {ref}`OpenVPN clients <openvpn-client-implementations>` provides a list of client implementations that can be used with a GUI across platforms.

```{toctree}
:hidden:

intro-to/wireguard-vpn
OpenVPN clients <security/openvpn-client-implementations>
```

## See also

* How-to: {ref}`how-to-security`