```mermaid
graph TD
  %% Host and Bridges
  subgraph Host_Machine_LXD
    H0[LXD Host]
    H0 --> B1[br-lan]
    H0 --> B2[br-wan]
  end

  %% LAN Zone
  subgraph LAN_Zone
    B1 --> R1[Router: VyOS or Ubuntu]
    R1 --> C1[Client1: IPv6-only]
    R1 --> C2[Client2: Dual-Stack]
    R1 --> C3[Client3: IPv4-only]
    R1 --> S1[WebServer: Dual-Stack]
  end

  %% WAN Zone
  subgraph WAN_Zone
    B2 --> R2[ISP Router]
    R2 --> EXT[External IPv6 Service]
  end

  %% Logical Routing
  R1 --> R2
  C1 --> R1
  C2 --> R1
  C3 --> R1
```