SSH Tunnel

Connect to databases that aren't directly reachable from Databasement: in private networks, behind a bastion/jump host, or on a remote Docker host whose database ports aren't published.

How it works

Databasement runs ssh -N -L <localPort>:<host>:<port> before each backup or restore and closes it afterward. SSH credentials are encrypted at rest.

No database tools needed on the SSH host

The dump and restore tools (mariadb-dump, pg_dump, mongodump, and so on) run inside the Databasement container and are NOT NEEDED on the SSH host.

Configuration

Enable SSH Tunnel on the database server and point it at the SSH host:

Field	Description
SSH Host	SSH server hostname or IP (bastion, jump host, or remote Docker host)
SSH Port	SSH port (default: 22)
SSH Username	SSH user
Auth Type	Password or Private Key (with optional passphrase)

Reusing an SSH configuration

Once you've saved an SSH config, the form offers Use existing (pick a saved config) or Set up a new SSH config. Reusing one lets several database servers share the same host connection — update it once and every server that references it follows.

Generating an SSH key

With Auth Type set to Private Key, the form can Generate a new Ed25519 keypair for you. Copy the displayed public key into ~/.ssh/authorized_keys on the SSH server before saving — it's shown only once and the public key isn't stored.

Backing up databases on a remote host

When databases run in Docker containers on a remote machine with ports only on an internal network, the tunnel reuses the same SSH access you already use to manage that host — no separate agent is needed, and the database stays private.

Publish the database port to the host's loopback, so it's reachable from the host but not from the network:

services:
  db:
    image: postgres:16
    ports:
      - "127.0.0.1:5432:5432"

Set the database Host to 127.0.0.1 and Port to 5432. Loopback is exactly where the tunnel terminates, so Databasement can reach the database while the network cannot.

Optional: SSH server in the stack

If the host doesn't expose SSH — or you'd rather not publish the database port at all — add a small SSH server to the same Compose project. Only the SSH port is published; Databasement reaches the database by its service name over the project's default network.

services:
  db:
    image: postgres:18

  sshd:
    image: lscr.io/linuxserver/openssh-server
    environment:
      USER_NAME: databasement
      PUBLIC_KEY: "ssh-ed25519 AAAA... databasement-tunnel"
      DOCKER_MODS: linuxserver/mods:openssh-server-ssh-tunnel
    ports:
      - "2222:2222"   # only SSH is published — not the database

Point the SSH Tunnel at the host on port 2222, then set the database Host to db and Port to 5432 — the service name resolves on the project's default network.

For same-host containers sharing a Docker network (no SSH), see Docker Networking instead.

Security

Keep the database private

What matters most is that the database is not reachable from the public internet: either because its host is on a private network, or because you bound the port to loopback (127.0.0.1:5432:5432).

Optionally, restrict the SSH key to forwarding only in authorized_keys:

restrict,port-forwarding ssh-ed25519 AAAA... databasement-tunnel