OpenSSH Server

Ansible role to configure the OpenSSH Server SSHD. The main goal of this role is to manage the sshd.conf file. And some additional parts like deploying the defined ssh host keys at the configured path.

Pro Tipp

Use Eliptic cureve cryptografie for your ssh keys:

ssh-keygen -t ed25519

The default values of this role will only allow ed25519 keys. But you can change that obviously if you like.

intended use

This role is designed to manage linux hosts with the following roles. This role here basically only focuses on a good configuration of sshd and can define which users are allowd to use connect via ssh and which ssh key types are allowd. Other roles distribute ssh public keys, creating users and configure sudo permission, roll out dotfiles or install a number of useful packages.

A list of suggested roles to manage your linux host:

• do1jlr.base install some useful packages
• do1jlr.users create user and manage sudoers
• do1jlr.auth deploy ssh pubkeys
• do1jlr.sshd (this one)
• do1jlr.dotfiles deploy some fancy dotfiles

Good to know:

The listed roles use the same variables to create accounts, admins and so on. But the roles have to run in the correct order to work properly. For example you can't deploy a ssh public key for a user that is not created.

Some Variables explained

Remember: Have a look into defaults/main.yml for all possible variables.

• SSH Port
  The OpenSSH Port is defined with the variable sshd__port: 22. Change it if you wish.

• Allowed Users and Groups
  The default users that are allowd to login come from the users: {} list.
  The same users: {} variable is used in the other recomended ssh roles.
  A example to allow the login for the users and groups called l3d and ottojo are:

users:
  l3d:
    - l3d
  ottojo:
   - ottojo@uni
   - ottojo@home

• SSH Login via Passwort
  The SSH Passwort auth is set to false via sshd__password_authentication: false. This won't allow you to use your passwort to login via SSH.

• Manage SSH Key Types
  By default this role configure which ssh key types are allowed to login. If you don't want to define that change the sshd__manage_key_types: true variable.

• Define allowed ssh key types
  The allowed SSH Key Types are defined with this list. Some of them are commented out.
  Please not that by defualt only ed25519 keys are allowed. Keep that in mind if you are using a rsa key.

  sshd__key_types:
  - 'ed25519'
  # - 'rsa'
  # - 'ecdsa'
  # - 'dsa' # (do not use!)

• Advanced SSH Algorithm Settings
  You can define the used Key and Kex Algorithm here to. For the default values and some examples for the variables sshd__key_algorithmus and sshd__kex_algorithmus have a look into defaults/main.yml. You can disable it by setting sshd__manage_key_algorithmus and sshd__manage_kex_algorithmus to false.

• force new SSH Features
  If you know that you use a ssh version >8 you can optionally define it with true/false with the sshd__version_is_above_eight variable.

Files

The main task of this role is to configure the sshd.conf file.

References

• Secure Secure Shell

Testing

This role is tested with some linting tests. Sadly I don't know how to run this role in a docker container because systemd is involved... If you have ideas how to improve testing please dend me a message, open a issue or Pull Request. If you want to find out more about our tests, please have a look at the github marketplace.

test status	Github Marketplace
	publish-ansible-role-to-galaxy
	yamllint-github-action
	ansible-lint action