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docs: add DNS setup plan documentation

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# Project Blueprint: High-Availability DNS Stack, Network Honeypot & VLAN Security Architecture
## 1. Project Objectives & Current State Assessment
### 1.1 Objectives
1. **Enterprise-Grade DNS Stack:**
- Deploy a resilient, scalable, dual-cluster DNS architecture across **Aerodrome** (`local`) and **Spaceport** (`c-m-4fgkl75b`).
- Implement **Pi-hole** as the front-end ad/malware filtering and caching engine.
- Implement **Technitium DNS Server** as the authoritative local DNS resolver (`snarfnet.net` split-horizon and PTR zones) and recursive DNS-over-HTTPS (DoH) upstream.
- Ensure Active-Active / High Availability across both clusters with zero rate-limiting bottlenecks.
2. **Network Security & Honeypot:**
- Deploy an automated, containerized honeypot (**OpenCanary** or **Cowrie**) with centralized logging and instant alerts to Gotify / Zabbix.
3. **VLAN Segmentation & Firewall Policy Hardening:**
- Audit and enforce inter-VLAN firewall rules on the **UniFi Dream Machine Pro (UDM Pro)** (`140.44.4.1`).
- Isolate Smart Home / IoT, Storage, and Guest traffic from the Management/Infrastructure plane.
- Apply Kubernetes `NetworkPolicy` resources to restrict east-west namespace traffic.
---
### 1.2 Inspection of Existing Cluster "Stubs"
We probed both clusters and discovered why the existing DNS implementations stalled:
| Cluster | Component | Current State | Root Cause Failure | Recommendation |
|---|---|:---:|---|---|
| **Aerodrome** (`140.44.4.11`) | `pihole` (deploy) | `0/1 Pending` | PVC `pihole` does not exist (`FailedScheduling`) | **Delete and rebuild cleanly** |
| **Aerodrome** (`140.44.4.11`) | `technitium-dns` (deploy) | `0/1 Pending` | PVC `technitium-longhorn-pvc` does not exist | **Delete and rebuild cleanly** |
| **Aerodrome** (`140.44.4.11`) | `pihole-dns-tcp/udp` | NodePort | Mapped to ephemeral high ports (`32655`/`31195`); standard DNS clients cannot query NodePorts | **Replace with Port 53 LoadBalancer VIP** |
| **Spaceport** (`140.44.4.41`) | `pihole` (deploy) | `1/1 Running` | Uses unmanaged local storage, exposed via NodePort only | **Delete and replace with unified manifest** |
| **Spaceport** (`140.44.4.41`) | `technitium-dns` (deploy) | `0/1 Pending` | PVC `technitium-longhorn-pvc` missing | **Delete and rebuild cleanly** |
> [!IMPORTANT]
> **Decision: Clean Teardown & Declarative Deployment.** Rather than patching fractured, incomplete stubs, we will prune the orphaned resources in `infra` and `infrastructure` and deploy a unified, declarative GitOps stack with dedicated Longhorn storage volumes and MetalLB VIPs on standard port 53.
---
## 2. High-Availability DNS Architecture (Pi-hole + Technitium)
```mermaid
flowchart TD
subgraph Clients["LAN Clients across all VLANs (VLAN 20, 40, 50, Guest)"]
ClientDevices["Laptops, Phones, Servers, IoT"]
end
subgraph UDM["UniFi Dream Machine Pro (140.44.4.1)"]
DHCP["DHCP Options 6:<br>Primary DNS: 140.44.4.35 (Aerodrome VIP)<br>Secondary DNS: 140.44.4.65 (Spaceport VIP)"]
end
subgraph AeroCluster["Aerodrome K3s Cluster"]
AeroVIP["MetalLB VIP: 140.44.4.35:53 (UDP/TCP)"]
AeroPihole["Pi-hole Instance 1<br>(Ad-blocking, Caching, FTL rate-limit: 0)"]
AeroTech["Technitium Instance 1 (Primary Authoritative)<br>(snarfnet.net Zone, PTR Records, DNSSEC)"]
AeroStorage["Longhorn Persistent Volume"]
end
subgraph SpaceCluster["Spaceport K3s Cluster"]
SpaceVIP["MetalLB VIP: 140.44.4.65:53 (UDP/TCP)"]
SpacePihole["Pi-hole Instance 2<br>(Ad-blocking, Caching, FTL rate-limit: 0)"]
SpaceTech["Technitium Instance 2 (Secondary Authoritative)<br>(Zone Transfer AXFR/IXFR from Primary)"]
SpaceStorage["Longhorn Persistent Volume"]
end
subgraph Upstream["Encrypted Upstream Resolvers"]
DoH["DNS-over-HTTPS (Quad9 / Cloudflare / Mullvad)"]
end
ClientDevices -->|Queries 140.44.4.35| AeroVIP
ClientDevices -.->|Fallback 140.44.4.65| SpaceVIP
AeroVIP --> AeroPihole
SpaceVIP --> SpacePihole
AeroPihole -->|Recursive / Local Lookup| AeroTech
SpacePihole -->|Recursive / Local Lookup| SpaceTech
AeroTech <==>|Automatic Zone Replication (AXFR)| SpaceTech
AeroTech -->|Encrypted Upstream| DoH
SpaceTech -->|Encrypted Upstream| DoH
AeroPihole --- AeroStorage
AeroTech --- AeroStorage
SpacePihole --- SpaceStorage
SpaceTech --- SpaceStorage
```
### 2.1 Solving the Historical Rate-Limiting & Performance Bottleneck
Your earlier Raspberry Pi Unbound/Pi-hole suffered when local devices (especially smart home polling, K8s CoreDNS forwards, and mobile apps) sent bursts of queries, tripping Pi-hole FTL's default rate-limit (`1000 queries in 60s per client`) and saturating single-threaded Unbound.
**How our cluster architecture resolves this:**
1. **Configurable Rate Limiting:**
- Set `FTLCONF_RATE_LIMIT=0` (or `10000/60` for WAN only) in the Pi-hole configuration so internal bursts are never blocked.
2. **Technitium Engine vs. Unbound:**
- Technitium is built on .NET 8/9 with an asynchronous, high-throughput DNS engine capable of handling tens of thousands of QPS without degrading.
- Built-in caching with negative caching and aggressive prefetching ensures queries are answered from RAM in `<0.5ms`.
3. **Clustered Failover:**
- MetalLB VIP on Aerodrome (`140.44.4.35`) and Spaceport (`140.44.4.65`) guarantees high availability: if an entire Kubernetes node or cluster is undergoing maintenance, clients seamlessly failover to the secondary VIP without DNS interruption.
4. **Zone Synchronization:**
- Aerodrome acts as the primary Technitium DNS server.
- Spaceport acts as the secondary Technitium DNS server, replicating zones via standard DNS NOTIFY / AXFR transfers automatically.
---
## 3. Network Security & Honeypot Architecture
```mermaid
flowchart LR
subgraph VLANs["Network VLAN Segments (UDM Pro)"]
VLAN20["VLAN 20: Infra / Management<br>(140.44.4.0/24)"]
VLAN40["VLAN 40: Storage<br>(14.10.10.0/24)"]
VLAN50["VLAN 50: Smart Home / IoT<br>(14.4.4.0/24)"]
VLAN90["VLAN 90: Isolated DMZ / Honeypot<br>(14.99.99.0/24)"]
VLAN80["VLAN 80: Guest Network<br>(14.80.80.0/24)"]
end
subgraph UDM_FW["UDM Pro Firewall Rules"]
DropInterVLAN["Block Inter-VLAN Routing"]
AllowEstablished["Allow Established & Related"]
AllowDNS["Allow Port 53 to DNS VIPs"]
end
subgraph SecurityCluster["Security Monitoring Services"]
Honeypot["OpenCanary / Cowrie Honeypot<br>(Simulating SSH, HTTP, SMB, RDP)"]
GotifyAlert["Gotify Alerting Bridge<br>(Instant Mobile Notification)"]
ZabbixLog["Zabbix / Syslog Telemetry"]
end
VLAN50 -.->|Blocked from accessing| VLAN20
VLAN80 -.->|Blocked from accessing| VLAN20
VLAN80 -.->|Blocked from accessing| VLAN40
VLAN50 -->|Allowed only port 53| DropInterVLAN
VLAN90 --> Honeypot
Honeypot -->|Triggered Event| GotifyAlert
Honeypot -->|Audit Event| ZabbixLog
```
### 3.1 Honeypot Implementation: OpenCanary / Cowrie
* **OpenCanary:**
* Low-interaction, highly modular honeypot that exposes simulated services:
* Port 22 (SSH fake login banner)
* Port 80 / 8080 (Fake router admin login)
* Port 445 (Fake SMB share)
* Port 3389 (Fake RDP prompt)
* Port 21 (Fake FTP)
* Any packet or connection attempt to these ports triggers an immediate high-priority alert via webhook to Gotify and logs to syslog/Zabbix.
* **Placement Options:**
* Option A: Deployed on a dedicated honeypot IP in the IoT/Guest subnet to detect lateral movement.
* Option B: Containerized pod in Spaceport with hostPort binding to a decoy IP.
### 3.2 UDM Pro Firewall Rules Matrix
| Rule Name | Direction | Source | Destination | Action | Purpose |
|---|---|---|---|:---:|---|
| `Allow-Established-Related` | `LAN IN` | Any | Any | **ACCEPT** | Allows responses to existing connections |
| `Allow-DNS-Traffic` | `LAN IN` | All VLANs | `140.44.4.35`, `140.44.4.65` (port 53) | **ACCEPT** | Allows all devices to query the DNS stack |
| `Allow-NTP-Traffic` | `LAN IN` | All VLANs | `140.44.4.11`, `14.4.4.44` (port 123) | **ACCEPT** | Allows Chrony time synchronization |
| `Isolate-IoT-to-Infra` | `LAN IN` | `VLAN 50 (SmartHome)` | `VLAN 20 (Infra)`, `VLAN 40 (Storage)` | **DROP** | Prevents compromised IoT devices from pivoting into servers |
| `Isolate-Guest-Network` | `GUEST IN` | `VLAN 80 (Guest)` | RFC1918 / Private Subnets | **DROP** | Isolates guest devices to Internet-only |
| `Isolate-Storage-VLAN` | `LAN IN` | Non-Storage Subnets | `VLAN 40 (14.10.10.0/24)` | **DROP** | Restricts Synology NFS/iSCSI to hypervisors and K8s storage nodes |
---
## 4. Phased Execution Roadmap
### Phase 1: Clean Up Legacy Stubs
- Delete broken deployments, services, and lingering pods in namespace `infra` (Aerodrome) and `infrastructure` (Spaceport).
- Verify MetalLB IP pool allocations:
- Allocate `140.44.4.35` on Aerodrome for Primary DNS.
- Allocate `140.44.4.65` on Spaceport for Secondary DNS.
### Phase 2: Deploy Pi-hole + Technitium on Aerodrome (Primary Stack)
- Create Longhorn PVCs for Pi-hole config (`etc-pihole`, `etc-dnsmasq`) and Technitium config (`technitium-data`).
- Deploy Technitium DNS container (port 5353 internally).
- Deploy Pi-hole container (port 53 externally via MetalLB `140.44.4.35`, upstream pointing to Technitium `127.0.0.1:5353`).
- Configure `FTLCONF_RATE_LIMIT=0` and subscribe to standard curated blocklists.
- Configure `snarfnet.net` forward and reverse zones in Technitium.
### Phase 3: Deploy Pi-hole + Technitium on Spaceport (Secondary Stack)
- Deploy identical stack on Spaceport bound to MetalLB VIP `140.44.4.65`.
- Establish Technitium zone replication between Primary (Aerodrome) and Secondary (Spaceport).
- Test dual-stack failover by querying both VIPs independently.
### Phase 4: Network Honeypot & Alerting Setup
- Deploy OpenCanary / Cowrie with active listeners on decoy ports.
- Configure Gotify webhook integration for instant mobile push notifications upon probe detection.
### Phase 5: UDM Pro Network Firewall & VLAN Policy Enforcement
- Configure DHCP on UDM Pro to distribute `140.44.4.35` and `140.44.4.65` across all VLANs.
- Apply and verify LAN IN / GUEST IN firewall rules on UDM Pro.
- Apply Kubernetes `NetworkPolicy` objects for cluster namespace segmentation.