SSH access

Manage SSH keys and password authentication for a host, and decide whether the host or its group has the last word.

The host's SSH tab controls how you and your team connect to a host over SSH. From here you manage the public keys allowed to log in and whether password-based login is permitted.

The SSH tab of a host
The SSH tab of a host

This tab covers:

  • SSH keys - manage the public keys allowed to log in
  • Password authentication - allow or disable password-based login
  • Overriding a group setting - make this host's choice win
  • SSH port - change the port SSH listens on

SSH keys

The ssh_keys list defines the public SSH keys allowed to access the server. Add, edit, or delete keys as your team changes.

Each key supports an optional name or label to help you identify its owner or purpose. Both ed25519 and RSA (Rivest-Shamir-Adleman) keys are supported. For a step-by-step walkthrough of generating a keypair, see Add an SSH key.

To add a key:

  1. Open the SSH tab for the host.
  2. Select Add SSH key.
  3. Paste the public key.
  4. Optionally enter a name or label for the key.
  5. Save your changes.

Inherited group keys

SSH keys can also be defined at the group level. When a host belongs to a group, it inherits the group's SSH keys in addition to any keys defined directly on the host. This lets you grant a set of keys access across many hosts at once. See Groups for how inheritance works.

Password authentication

Only allow SSH authentication by keys controls whether password-based SSH login is permitted. Switch it on and users can connect only with an SSH key. In the configuration this is ssh_passwords: false - the checkbox is worded the other way round from the key it writes.

Before disabling password authentication, confirm that every user who needs access has a working SSH key configured so that no one is locked out.

Overriding a group setting

When a host belongs to a group, the group can also decide whether passwords are allowed - and by default the stricter setting wins: if any of the host's groups disables password login, it is disabled on the host too, whatever the host itself says.

Enforce host SSH password setting changes that. Switch it on and the host's own choice above applies, ignoring its groups. The checkbox appears only when the host is in at least one group.

Enforce What decides
Off (default) A group that disables password login wins. Otherwise the host's own setting applies.
On The host's setting applies, whether that allows passwords or not.

SSH port

The ssh_port setting controls which port the SSH service listens on. Changing it from the default can reduce noise from automated scans.