Linux Remote Desktop Support

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<div class="atitle2">How to do<br>
    <div class="atitle" style="font-size:200% !important"><span class="db8orange">Linux Remote Desktop Support</span></div>
        <br><br><br><br>
        <span class="apage1">by Peter Martin / <a href="https://db8.nl" target="_blank">db8.nl</a></span>
        <br>
        <span class="apage1">slides: <a href="https://slides.db8.nl" target="_blank">https://slides.db8.nl</a></span>
        <style>.atitle{text-shadow: 2px 2px 2px #000;}
        .atitle2{text-shadow: 2px 2px 2px #000;}
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        <div style="margin: 0 auto;">
        <a href="https://db8.nl" title="Joomla Specialist db8 Nijmegen" target="_blank">
            <img height="50" style="border:0;background:transparent;margin-right:20px;
            box-shadow: 0 0 0 rgba(0, 0, 0, 0.15);" src="images/db8-logo.svg" alt="db8">
        </a>
    </div>
</div>

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<div class="title"><span class="db8orange">Computer says No?</span></div>

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### Remote Support

- Eessential for IT and user assistance
- Common tools: TeamViewer, AnyDesk
- Easy to use but with disadvantages

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#### Issues with TeamViewer and AnyDesk

- **Closed source**: You cannot verify what happens with your data.
- **Paid licenses**: 
  - Free only for personal use
  - business use is expensive.
- **Privacy concerns**: All sessions route through their servers.
- **Vendor lock-in**: 
  - No self-hosted option
  - depended entirely on their infrastructure.
- **Limitations**: Forced updates, blocked access, or commercial-use detection.

</span>

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<div class="title"><span class="db8orange">Remote Support</span></div>

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### Why Open Source Is Better

- **Transparency**: Source code is public.
- **Security**: Auditable and self-hosted.
- **Freedom**: No vendor lock-in.
- **Cost**: Free for both personal and commercial use.
- **Active community**: Continuous improvements and shared knowledge.

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### Open-Source Alternatives

- **RustDesk**
    - Modern, written in Rust.
    - Cross-platform and efficient.
    - Peer-to-peer or relay-based connections.
- **MeshCentral**
    - Node.js-based remote management.
    - Ideal for multi-device or enterprise setups.
    - Browser-based control interface.

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<div class="title"><span class="db8orange">How RustDesk Works</span></div>

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### How RustDesk Works

- Client–Server model with optional relay.
- Designed for secure and private remote sessions.

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### RustDesk Architecture

- **HBBS (Rendezvous Server)**
  - Host-Based Broker Server
  - Handles client registration and NAT traversal coordination.
  - Acts as a connection broker.

- **HBBR (Relay Server)**
  - Host-Based Broker Relay
  - Relays encrypted traffic when direct peer-to-peer is not possible.
  - Ideal for firewalled or NATed systems.

</span>

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### RustDesk Connection Flow

1. Client connects to **HBBS** to register.
2. Peers locate each other through the broker.
3. If direct P2P fails, data routes through **HBBR**.
4. All communication uses **end-to-end encryption**.

</span>

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### RustDesk Security Model

- Encrypted connections using TLS.
- Public/private key pairs for authentication.
- End-to-end encryption ensures no one can intercept the session.

</span>

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<div class="title">RustDesk <span class="db8orange">Client</span></div>

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### Setting Up RustDesk Client 1/2

#### Flatpack
```bash
sudo apt update
sudo apt install flatpak -y
sudo flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
flatpak install flathub com.rustdesk.RustDesk -y
```

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### Setting Up RustDesk Client 2/2

#### .deb version

```bash
wget https://github.com/rustdesk/rustdesk/releases/download/1.4.2/rustdesk-1.4.2-x86_64.deb
sudo dpkg -i rustdesk-1.4.2-x86_64.deb
sudo apt install --f
sudo dpkg -i rustdesk-1.4.2-x86_64.deb

```

---

<div class="title">RustDesk <span class="db8orange">Server</span></div>

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#### Use <span class="db8orange">RustDesk’s public relay servers</span>

- Easy to setup 
- (not for me)
  - I could connect laptop A to laptop B
  - couldn't connect laptop B to laptop A

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#### <span class="db8orange">Self-hosted</span> with your own HBBS + HBBR servers.

- Run Docker containers:
  - hbbs – starts the rendezvous (broker) server
  - hbbr – starts the relay server
  - Configure ports (TCP/UDP 21115–21119 default).
  - Update RustDesk clients with your server address in the “ID/Relay” settings.

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### Docker compose.yml file 1/2

```yaml
services:
  hbbr:
    container_name: hbbr
    image: rustdesk/rustdesk-server:latest
    command: hbbr
    volumes:
      - ./data:/root
    network_mode: "host"
    restart: unless-stopped
    healthcheck:
      test: ["CMD-SHELL", "ss -ltn | grep -q ':21117'"]
      interval: 30s
      timeout: 5s
      retries: 5
```

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### Docker compose.yml file 2/2

```yaml
  hbbs:
    container_name: hbbs
    image: rustdesk/rustdesk-server:latest
    # Verwijs hbbs naar hbbr op dezelfde host/domein
    command: hbbs -r rustdesk.8db.nl:21117
    volumes:
      - ./data:/root
    network_mode: "host"
    depends_on:
      - hbbr
    restart: unless-stopped
    healthcheck:
      test: ["CMD-SHELL", "ss -ltn | egrep -q ':21114|:21115|:21116|:21118'"]
      interval: 30s
      timeout: 5s
      retries: 5
```

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### Verification

- Test connection between two clients.
- Ensure NAT traversal and relay fallback works.
- Optional: Enable encryption key verification.

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### Request server encryption key

```bash
# sed -n '1p' ./data/id_ed25519.pub
```

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#### id_ed25519.pub

- ed25519 = EdDSA + Curve25519 (twisted Edwards version)
  - **EdDSA** is a digital signature scheme 
  - using a **variant of the Schnorr signature** 
  - based on  **twisted Edwards curves**
  - (anyone?)

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### Check on server check if devices work ok

```bash
# docker logs hbbs | grep update_pk
```

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<div class="title">Questions? <span class="db8orange">Anyone, anyone?</span></div>

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## Photo Credits

<ul style="font-size:50%">
<li>All photos generated with ChatGPT 5</li>
</ul>

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