How it works
The agent on your server
The installer puts the agent inC:\Program Files\Raff\Guardian and its data in C:\ProgramData\Raff\Guardian, and runs it as the RaffGuardian Windows service. The service starts with Windows, and Windows restarts it if it fails. The Server card on the Overview shows how much processor and memory Raff Guardian itself uses.
Its own key
At install, the agent makes its own key pair on the server. The private key stays in the data folder, which only Administrators and the system account can read; Raff only ever receives the public half. A reinstall makes a new key.Reports every minute
Every minute the agent checks the server and sends a signed report to Raff over HTTPS: processor and memory, disk space, pending Windows updates, services, failed sign-ins, firewall and Microsoft Defender state, and more. It sends the full state every 15 minutes and otherwise only what changed. Raff accepts a report only when its signature matches the key made at install. If Raff cannot be reached, the agent keeps its reports and sends them when the connection is back. Blocking attackers does not wait for Raff: the agent does that on the server itself. See Privacy and data.Changes are signed by Raff
Raff Guardian makes a change only through a plan that Raff signs, for example “install Windows updates” or “block this address”. Plans travel back in the answer to the agent’s own report, so nothing ever connects in to your server. Before it runs a plan, the agent checks that:- Raff’s signature is valid,
- the plan is for this server and has not expired (a plan not run within 30 minutes expires),
- it is an action built into the agent. The agent has no way to run any other command.
Signed releases and self-update
Raff signs every release of Raff Guardian, and the agent checks the signature before it installs anything:- At install, the command checks the installer against the fingerprint Raff published for it, and the installer checks the agent the same way before it changes anything on the server. If either does not match, it stops: “Nothing was installed.”
- On every update, the agent checks Raff’s signature on the release with a key built into the agent itself, then downloads the new version only from Raff’s release location, with the exact size and fingerprint the signed release names. A release that fails any check is refused.
When the agent goes quiet
If Raff hears nothing for 5 minutes, the Guardian tab shows “Raff Guardian is not reporting.” above its sections and the finding Contact with your server opens. When reports come back, the finding closes and Activity says how long contact was lost. A server that was turned off shows that instead, for example “Server has been off since 14:02. You shut it down from the dashboard.”When to use it
- You run Windows servers and want attackers blocked, updates installed and services kept running without logging in every day.
- You want a record of every change made to the server, with what it was before and after.
- You want to see problems (low disk, a stopped service, Windows not activated) before your users do.
Trade-offs / limits
- Windows Server only. Raff Guardian does not run on Linux yet.
- The agent needs outbound HTTPS to Raff. With no connection it keeps watching and blocking, but Raff cannot act on its reports until they arrive.
- Raff Guardian runs only the actions built into it. It does not run your own scripts or commands.
Related
Modes and permissions
What Raff Guardian may change on its own.
Install on an existing server
Run the install command.