106 lines
3.7 KiB
Markdown
106 lines
3.7 KiB
Markdown
---
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layout: default
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title: Connecting
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description: How to reach downstream hosts through the jump host — the username grammar, the interactive picker, SFTP/WinSCP, and what access you get.
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---
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# Connecting
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You reach a downstream host two ways: name the target in your username, or log
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in plain and pick it from a menu. Either way you authenticate **once**, to the
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jump host, with your directory credentials.
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## The username grammar
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```
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{uid}_-_{target}
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```
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- `{uid}` — your directory username.
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- `_-_` — the separator (legal in an SSH username everywhere, including WinSCP).
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- `{target}` — the host to reach: a directory **slug** (`host_web01` or just
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`web01`), the host's **display name**, its **IP**, or the hostname in its
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directory `address`.
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```bash
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ssh alice_-_web01@jump.example.com # by slug (host_ prefix optional)
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ssh alice_-_10.0.0.10@jump.example.com # by IP (must be a host you can reach)
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```
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If the target matches a host your directory groups grant, you're bridged
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straight to its `sshd` — same as if you'd SSH'd directly, but through the
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audited jump host.
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## SFTP / WinSCP / scp
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Because the whole route is encoded in the username, file transfer tools that
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only take one connection string work with no extra configuration:
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```bash
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sftp -P 2222 alice_-_web01@jump.example.com
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scp -P 2222 file.txt alice_-_web01@jump.example.com:/tmp/
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```
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**WinSCP:** set Host name to `jump.example.com`, Port to `2222`, and User name
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to `alice_-_web01`. SFTP is bridged as an opaque byte stream, so all operations
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(browse, upload, download, rename) work normally.
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## The interactive picker
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Log in with just your username and you get a TUI list of every host you can
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reach:
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```bash
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ssh alice@jump.example.com
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```
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- **↑ / ↓** move the selection
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- **type** to filter the list incrementally
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- **Enter** connect to the highlighted host
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- **number keys** jump straight to that row
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- **q** or **Ctrl-C** to quit
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Pick a host and you're bridged into it. The picker only ever lists hosts your
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directory access allows — it doubles as "what can I reach from here?"
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## What you can reach
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The set of hosts is computed per login: your LDAP group memberships intersected
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with the SSO directory's hosts (via the `host_<name>_access` groups the
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directory auto-creates for each machine). To get access to a new host, an admin
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adds you to that host's access group in the SSO — nothing on the jump host
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changes.
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Targets that don't resolve to a host you're allowed to reach are refused (and
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audited). Raw IPs that aren't a known directory host are denied by default.
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> On a [standalone](architecture.html#standalone-mode) jump host (no LDAP/SSO),
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> every registered host is reachable by every registered user — there's no
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> group-based restriction to ask an admin about.
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## Authentication
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The jump host authenticates **you** against the directory:
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- **Public key** — matched against your `sshPublicKey` entries in LDAP. Use your
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normal SSH key; the client picks it automatically.
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- **Password** — your directory password (LDAP bind). Password auth is often
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restricted to local networks or disabled entirely on a public jump host
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(keys-only) — check with your operator.
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You never manage a separate credential for the downstream host: the jump host
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handles onward authentication for you (see
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[Architecture](architecture.html#per-user-key-injection)).
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## First connection to a host
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The very first time you reach a given downstream host, the jump host provisions
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its access key for you behind the scenes. If that first attempt races the
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directory's key-cache refresh you may see a brief
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```
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jump-host: first-time key propagation, retrying…
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```
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and it reconnects automatically. Subsequent connections are immediate.
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