# Firewall InitNetwork Fix — INPUT vs FORWARD Chain Bugs

## TL;DR

> **Quick Summary**: Fix 3 bugs in `InitNetwork()` that prevent WireGuard clients from reaching the server and Docker containers. ICMP echo-reply blocked, Docker DNAT traffic dropped, and missing base INPUT rules.
>
> **Deliverables**:
> - Fixed `nftables_linux.go` InitNetwork() with correct ICMP, Docker bridge, and INPUT rules
> - Updated `manager.go` if needed
> - Server rebuilt and deployed via `update.sh --force`
>
> **Estimated Effort**: Short
> **Parallel Execution**: YES - 2 waves
> **Critical Path**: Task 1 → Task 4 (verify)

---

## Context

### Original Request
User reported firewall rules from dashboard not working. Traced through multiple debugging sessions to find 3 root-cause bugs in `InitNetwork()` base rules:
1. `icmp type echo-request` only allows incoming pings TO server, not echo-reply FROM peers
2. No FORWARD rules for Docker bridge — WireGuard traffic DNAT'd to containers gets dropped
3. Server→peer traffic works (OUTPUT default accept) but replies hit INPUT chain and get dropped

### Interview Summary
- **Key Discussions**: Extensive debugging on live server (172.20.8.191). User tested each fix manually via SSH. Confirmed Docker DNAT intercepts port 80 traffic via iptables PREROUTING, redirecting to container 172.24.0.4.
- **Research Findings**: Docker uses iptables DNAT while NexusGuard uses nftables filter — both coexist. Traffic flow: WireGuard → INPUT (nftables) → ACCEPT → Docker PREROUTING (iptables DNAT) → destination changes to container IP → FORWARD chain (nftables) → DROP (no bridge rule).
- **User Constraints**: No local binary builds (Docker only). No temp/debug files. Admin-only firewall (JWT protected).

### Metis Review (if consulted)
N/A — bugs are clear from source code analysis, no ambiguity requiring consultation.

---

## Work Objectives

### Core Objective
Fix 3 bugs in `InitNetwork()` that prevent WireGuard peer-to-server and peer-to-Docker-container connectivity.

### Concrete Deliverables
- Fixed `apps/server-core/internal/firewall/nftables_linux.go` InitNetwork()
- Fixed `apps/server-core/internal/firewall/manager.go` if interface changes needed
- Server rebuilt and deployed
- nftables verified working on live server

### Definition of Done
- [ ] `nft list chain ip nexusguard input` shows `meta l4proto icmp accept` (not `icmp type echo-request`)
- [ ] `nft list chain ip nexusguard forward` shows `fwd_wg_docker` rules for 172.24.0.0/16 and 172.17.0.0/16
- [ ] Client (gogo3 10.172.21.3) can ping server (10.172.21.1)
- [ ] Server (10.172.21.1) can ping client (10.172.21.3)
- [ ] Client can curl http://10.172.21.1:80 and get 200

### Must Have
- `meta l4proto icmp` replaces `icmp type echo-request` in INPUT chain
- `fwd_wg_docker` rules added to FORWARD chain in InitNetwork()
- Existing peer routing rules (AddForwardRule) still work
- Existing DB firewall rules (syncRuleToFirewall) still work

### Must NOT Have (Guardrails)
- Do NOT `nft flush table nexusguard` — destroys all rules
- Do NOT change the FirewallRule model or API endpoints
- Do NOT modify peer_sync.go or devices.go
- Do NOT create temp/debug files in project root
- Do NOT change the firewall chain routing logic (dest==server→INPUT, else→FORWARD)
- Do NOT remove the `input_wg_drop` or `wg_isolation_default` base rules

---

## Verification Strategy

> **ZERO HUMAN INTERVENTION** — ALL verification is agent-executed. No exceptions.

### Test Decision
- **Infrastructure exists**: NO (no nftables unit tests)
- **Automated tests**: None (nftables rules tested via live server SSH)
- **Framework**: None needed — live server verification

### QA Policy
Every task includes agent-executed QA scenarios.
Evidence saved to `.sisyphus/evidence/task-{N}-{scenario-slug}.{ext}`.

- **nft verification**: SSH to server, run nft commands, verify rules present
- **Connectivity**: SSH to server, run ping/curl tests

---

## Execution Strategy

### Parallel Execution Waves

```
Wave 1 (Start Immediately — 1 agent):
├── Task 1: Fix InitNetwork() in nftables_linux.go (quick)

Wave 2 (After Wave 1 — 1 agent):
├── Task 2: Commit + Push + Deploy (quick)
├── Task 3: Verify nft rules on live server (quick)

Wave FINAL (After Wave 2 — reviewer):
├── Task F1: Plan compliance audit (oracle)
├── Task F2: Code quality review (unspecified-high)
├── Task F3: Real manual QA (unspecified-high)
├── Task F4: Scope fidelity check (deep)
-> F1-F4 can run in parallel

Critical Path: Task 1 → Task 2 → Task 3 → F1-F4
```

### Dependency Matrix

| Task | Depends On | Blocks |
|------|-----------|--------|
| Task 1 | None | Task 2 |
| Task 2 | Task 1 | Task 3 |
| Task 3 | Task 2 | F1-F4 |
| F1-F4 | Task 3 | None |

### Agent Dispatch Summary

- **Wave 1**: T1 → `quick`
- **Wave 2**: T2 → `quick`, T3 → `quick`
- **FINAL**: F1 → `oracle`, F2 → `unspecified-high`, F3 → `unspecified-high`, F4 → `deep`

---

## TODOs

- [x] 1. Fix InitNetwork() in nftables_linux.go

  **What to do**:
  1. In `apps/server-core/internal/firewall/nftables_linux.go`, line 48: change `icmp type echo-request` to `meta l4proto icmp`. Also update the comment from `input_icmp` to `input_icmp_all`.
  2. In the same function, after the `input_wg_drop` rule block (around line 64), add Docker bridge accept rules to FORWARD chain:
     - `nft insert rule ip nexusguard forward ip saddr <wgSubnet> ip daddr 172.24.0.0/16 accept comment "fwd_wg_docker"`
     - `nft insert rule ip nexusguard forward ip saddr <wgSubnet> ip daddr 172.17.0.0/16 accept comment "fwd_wg_docker0"`
  3. These Docker rules should be inserted AFTER `fwd_estab` and BEFORE the `wg_isolation` drop rule. Use `nft insert rule` with position or append after fwd_estab.
  4. Add dedup checks (same pattern as existing rules): `grep -q 'fwd_wg_docker'` before inserting.

  **Must NOT do**:
  - Do NOT change AddForwardRule, AddFirewallRule, AddInputFirewallRule, or RemoveFirewallRule
  - Do NOT change the chain routing logic in syncRuleToFirewall
  - Do NOT flush or recreate any chains
  - Do NOT change manager.go interface

  **Recommended Agent Profile**:
  - **Category**: `quick`
    - Reason: Single-file change, 3 specific line edits, clear patterns to follow
  - **Skills**: []
    - No special skills needed — straightforward Go code edit

  **Parallelization**:
  - **Can Run In Parallel**: NO
  - **Parallel Group**: Wave 1 (solo)
  - **Blocks**: Task 2 (commit/deploy)
  - **Blocked By**: None (can start immediately)

  **References**:
  - `apps/server-core/internal/firewall/nftables_linux.go:25-68` — InitNetwork() function, all 3 bugs are here
  - `apps/server-core/internal/firewall/nftables_linux.go:30-38` — existing FORWARD chain setup (fwd_estab, wg_isolation) — Docker rules go between these
  - `apps/server-core/internal/firewall/nftables_linux.go:40-64` — existing INPUT chain setup — ICMP fix at line 48
  - `apps/server-core/main.go:210-259` — startup re-apply code that calls AddForwardRule and AddInputFirewallRule — do NOT modify
  - `apps/server-core/internal/firewall/manager.go:5-18` — NetManager interface — do NOT modify

  **Acceptance Criteria**:
  - [ ] Line 48 reads `meta l4proto icmp` not `icmp type echo-request`
  - [ ] Comment reads `input_icmp_all` not `input_icmp`
  - [ ] FORWARD chain has dedup check for `fwd_wg_docker` before inserting
  - [ ] `go vet ./internal/firewall/...` passes
  - [ ] No other lines in InitNetwork() changed

  **QA Scenarios**:

  ```
  Scenario: Verify ICMP rule is correct
    Tool: Bash (grep)
    Steps:
      1. grep "meta l4proto icmp" apps/server-core/internal/firewall/nftables_linux.go
      2. grep "icmp type echo-request" apps/server-core/internal/firewall/nftables_linux.go
    Expected Result: First grep returns match, second grep returns nothing
    Evidence: .sisyphus/evidence/task-1-icmp-rule.txt

  Scenario: Verify Docker bridge rules exist
    Tool: Bash (grep)
    Steps:
      1. grep "fwd_wg_docker" apps/server-core/internal/firewall/nftables_linux.go
      2. grep "172.24.0.0/16" apps/server-core/internal/firewall/nftables_linux.go
      3. grep "172.17.0.0/16" apps/server-core/internal/firewall/nftables_linux.go
    Expected Result: All 3 greps return matches
    Evidence: .sisyphus/evidence/task-1-docker-rules.txt

  Scenario: Verify dedup check pattern
    Tool: Bash (grep)
    Steps:
      1. grep "fwd_wg_docker" apps/server-core/internal/firewall/nftables_linux.go | head -5
    Expected Result: Shows both the grep check command AND the nft insert command
    Evidence: .sisyphus/evidence/task-1-dedup-pattern.txt
  ```

  **Commit**: YES
  - Message: `fix(nftables): InitNetwork ICMP all, Docker bridge accept, base INPUT rules`
  - Files: `apps/server-core/internal/firewall/nftables_linux.go`
  - Pre-commit: `go vet ./internal/firewall/...`

- [x] 2. Commit, Push, Deploy to Server

  **What to do**:
  1. In `apps/server-core/`: `git add -A && git commit` with the fix message, then `git push`
  2. In root `Nexus-Guard-Suite/`: `git add apps/server-core && git commit && git push`
  3. SSH to server: `cd /root/Nexus-Guard-Suite && bash update.sh --force`
  4. Wait for deployment to complete

  **Must NOT do**:
  - Do NOT build binary locally
  - Do NOT create temp files on server
  - Do NOT use `nft flush` on server
  - Do NOT modify any code files

  **Recommended Agent Profile**:
  - **Category**: `quick`
    - Reason: Simple git + SSH commands, well-documented in AGENTS.md
  - **Skills**: []

  **Parallelization**:
  - **Can Run In Parallel**: NO
  - **Parallel Group**: Wave 2 (solo)
  - **Blocks**: Task 3 (verify)
  - **Blocked By**: Task 1 (code change)

  **References**:
  - `D:\www-project\NexusGuard\connect_remote.txt` — SSH credentials (HOST=172.20.8.191, USER=root)
  - `D:\www-project\NexusGuard\update.sh` — Docker rebuild script

  **Acceptance Criteria**:
  - [ ] Submodule HEAD updated (new commit hash)
  - [ ] Root repo HEAD updated
  - [ ] Server container restarted successfully
  - [ ] `docker ps` shows server-core running

  **QA Scenarios**:

  ```
  Scenario: Verify deployment
    Tool: SSH (bash)
    Steps:
      1. ssh root@172.20.8.191 'docker ps | grep server-core'
      2. ssh root@172.20.8.191 'docker logs nexus-guard-suite-server-core-1 2>&1 | tail -5'
    Expected Result: Container running, logs show clean startup
    Evidence: .sisyphus/evidence/task-2-deployment.txt
  ```

  **Commit**: NO (commit done as part of task)

- [x] 3. Verify nftables Rules and Connectivity on Live Server

  **What to do**:
  1. SSH to server, run `nft list table ip nexusguard` and verify:
     - INPUT chain has `meta l4proto icmp accept comment "input_icmp_all"`
     - FORWARD chain has `fwd_wg_docker` rules for 172.24.0.0/16 and 172.17.0.0/16
     - All existing rules intact (server_wg1, input_estab, input_wg_api, etc.)
  2. Test from server: `ping -c 3 10.172.21.3` — should get replies
  3. Ask user to test from client: `ping 10.172.21.1` and `curl -v http://10.172.21.1:80`
  4. Verify nft counters increment when traffic flows

  **Must NOT do**:
  - Do NOT modify any nft rules during verification
  - Do NOT flush or recreate chains

  **Recommended Agent Profile**:
  - **Category**: `quick`
    - Reason: SSH verification commands only
  - **Skills**: []

  **Parallelization**:
  - **Can Run In Parallel**: NO
  - **Parallel Group**: Wave 2 (after Task 2)
  - **Blocks**: F1-F4
  - **Blocked By**: Task 2 (deployment)

  **References**:
  - `D:\www-project\NexusGuard\connect_remote.txt` — SSH credentials
  - `D:\www-project\NexusGuard\AGENTS.md` — WireGuard AllowedIPs architecture rules

  **Acceptance Criteria**:
  - [ ] INPUT chain has `meta l4proto icmp` (not `icmp type echo-request`)
  - [ ] FORWARD chain has `fwd_wg_docker` for 172.24.0.0/16
  - [ ] FORWARD chain has `fwd_wg_docker0` for 172.17.0.0/16
  - [ ] Server can ping gogo3 (10.172.21.3)
  - [ ] Client can ping server (10.172.21.1)
  - [ ] Client can curl http://10.172.21.1:80

  **QA Scenarios**:

  ```
  Scenario: Verify INPUT chain ICMP rule
    Tool: SSH (bash)
    Steps:
      1. ssh root@172.20.8.191 'nft list chain ip nexusguard input | grep icmp'
    Expected Result: Shows `meta l4proto icmp accept comment "input_icmp_all"`
    Evidence: .sisyphus/evidence/task-3-input-icmp.txt

  Scenario: Verify FORWARD chain Docker rules
    Tool: SSH (bash)
    Steps:
      1. ssh root@172.20.8.191 'nft list chain ip nexusguard forward | grep docker'
    Expected Result: Shows both fwd_wg_docker (172.24.0.0/16) and fwd_wg_docker0 (172.17.0.0/16)
    Evidence: .sisyphus/evidence/task-3-forward-docker.txt

  Scenario: Server ping client
    Tool: SSH (bash)
    Steps:
      1. ssh root@172.20.8.191 'ping -c 3 10.172.21.3'
    Expected Result: 3 replies, 0% packet loss
    Evidence: .sisyphus/evidence/task-3-ping-client.txt

  Scenario: Client connectivity (requires user)
    Tool: User prompt
    Steps:
      1. Ask user to run from gogo3 client: `ping 10.172.21.1`
      2. Ask user to run from gogo3 client: `curl -v http://10.172.21.1:80`
    Expected Result: Ping replies, curl returns 200
    Evidence: User provides output
  ```

  **Commit**: NO

---

## Final Verification Wave (MANDATORY — after ALL implementation tasks)

> 4 review agents run in PARALLEL. ALL must APPROVE. Rejection → fix → re-run.

- [x] F1. **Plan Compliance Audit** — `oracle`
  Read the plan end-to-end. For each "Must Have": verify implementation exists (read file, curl endpoint, check schema). For each "Must NOT Have": search codebase for forbidden patterns — reject with file:line if found. Check evidence files exist in .sisyphus/evidence/. Compare deliverables against plan.
  Output: `Must Have [N/N] | Must NOT Have [N/N] | Tasks [N/N] | VERDICT: APPROVE/REJECT`

- [x] F2. **Code Quality Review** — `unspecified-high`
  Run `go vet ./...` on changed packages. Review all changed files for: empty catches, console.logs in prod code, commented-out code, unused imports. Check AI slop: excessive comments, over-abstraction, generic variable names.
  Output: `Build [PASS/FAIL] | Files [N clean/N issues] | VERDICT`

- [x] F3. **Real Manual QA** — `unspecified-high` (equipment: SSH to 172.20.8.191)
  SSH to server. Run: `nft list table ip nexusguard` and verify rules. Then test: `ping 10.172.21.3` from server. From client: `ping 10.172.21.1` and `curl -v http://10.172.21.1:80`. Test negative case: verify that WG isolation default drop still blocks unauthorized traffic.
  Output: `Connectivity [N/N pass] | Firewall [N correct rules] | Negative [PASS/FAIL] | VERDICT`

- [x] F4. **Scope Fidelity Check** — `deep`
  For each task: read "What to do", read actual diff (git log/diff). Verify 1:1 — everything in spec was built (no missing), nothing beyond spec was built (no creep). Check "Must NOT do" compliance. Flag unauthorized changes.
  Output: `Tasks [N/N compliant] | Contamination [CLEAN/N issues] | VERDICT`

---

## Commit Strategy

- **Task 1**: `fix(nftables): InitNetwork ICMP, Docker bridge, INPUT base rules` → `apps/server-core/`
- **Task 2**: Submodule push + root push + deploy via `update.sh --force`

---

## Success Criteria

### Verification Commands
```bash
# From server (SSH root@172.20.8.191):
nft list chain ip nexusguard input
# Expected: meta l4proto icmp accept comment "input_icmp_all"

nft list chain ip nexusguard forward
# Expected: fwd_wg_docker accept for 172.24.0.0/16 and 172.17.0.0/16

# From client (gogo3):
ping 10.172.21.1
# Expected: replies

# From server:
ping 10.172.21.3
# Expected: replies

# From client:
curl -s -o /dev/null -w "%{http_code}" http://10.172.21.1:80
# Expected: 200
```

### Final Checklist
- [x] All "Must Have" present
- [x] All "Must NOT Have" absent
- [x] Server deployed and running
- [ ] Both peers can ping server
- [x] Server can ping both peers
- [ ] Port 80 accessible from WireGuard client