Files
BanGUI/Docker/fail2ban-dev-config/README.md
Lukas 08b8f3872a fix: reload/stop jail 404 + access list simulator
Task 1 — fix Stop/Reload Jail returning 404
  Root cause: reload_jail and reload_all sent an empty config stream
  (["reload", name, [], []]).  In fail2ban's reload protocol the end-of-
  reload phase deletes every jail still in reload_state — i.e. every jail
  that received no configuration commands.  An empty stream means *all*
  affected jails are silently removed from the daemon's runtime, causing
  everything touching those jails afterwards (including stop) to receive
  UnknownJailException → HTTP 404.

  Fixes:
  - reload_jail: send ["start", name] in the config stream; startJail()
    removes the jail from reload_state so the end phase commits instead of
    deletes, and un-idles the jail.
  - reload_all: fetch current jail list first, build a ["start", name]
    entry for every active jail, then send reload --all with that stream.
  - stop_jail: made idempotent — if the jail is already gone (not-found
    error) the operation silently succeeds (200 OK) rather than returning
    404, matching the user expectation that stop = ensure-stopped.
  - Router: removed dead JailNotFoundError handler from stop endpoint.

  391 tests pass (2 new), ruff clean, mypy clean (pre-existing
  config.py error unchanged).

Task 2 — access list simulator
  - Docker/simulate_accesses.sh: writes fake HTTP-scan log lines in
    custom format (bangui-access: http scan from <IP> ...) to
    Docker/logs/access.log so the bangui-access jail detects them.
  - fail2ban/filter.d/bangui-access.conf: failregex matching the above.
  - fail2ban/jail.d/bangui-access.conf: polling jail on access.log,
    same settings as bangui-sim (maxretry=3, bantime=60s).
  - .gitignore: whitelist new bangui-access.conf files.
  - Docker/fail2ban-dev-config/README.md: added "Testing the Access
    List Feature" section with step-by-step instructions and updated
    Configuration Reference + Troubleshooting.
2026-03-06 19:49:31 +01:00

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# BanGUI — Fail2ban Dev Test Environment
This directory contains the fail2ban configuration and supporting scripts for a
self-contained development test environment. A simulation script writes fake
authentication-failure log lines, fail2ban detects them via the `bangui-sim`
jail, and bans the offending IP — giving a fully reproducible ban/unban cycle
without a real service.
---
## Prerequisites
- Docker or Podman installed and running.
- `docker compose` (v2) or `podman-compose` available on the `PATH`.
- The repo checked out; all commands run from the **repo root**.
---
## Quick Start
### 1 — Start the fail2ban container
```bash
docker compose -f Docker/compose.debug.yml up -d fail2ban
# or: make up (starts the full dev stack)
```
Wait ~15 s for the health-check to pass (`docker ps` shows `healthy`).
### 2 — Run the login-failure simulation
```bash
bash Docker/simulate_failed_logins.sh
```
Default: writes **5** failure lines for IP `192.168.100.99` to
`Docker/logs/auth.log`.
Optional overrides:
```bash
bash Docker/simulate_failed_logins.sh <COUNT> <SOURCE_IP> <LOG_FILE>
# e.g. bash Docker/simulate_failed_logins.sh 10 203.0.113.42
```
### 3 — Verify the IP was banned
```bash
bash Docker/check_ban_status.sh
```
The output shows the current jail counters and the list of banned IPs with their
ban expiry timestamps.
### 4 — Unban and re-test
```bash
bash Docker/check_ban_status.sh --unban 192.168.100.99
```
### One-command smoke test (Makefile shortcut)
```bash
make dev-ban-test
```
Chains steps 13 automatically with appropriate sleep intervals.
---
## Testing the Access List Feature
The **Access List** tab in BanGUI displays each individual matched log line
stored in fail2ban's database. A second jail — `bangui-access` — monitors
`Docker/logs/access.log` for simulated HTTP bot-scan entries.
### 1 — Run the access-scan simulation
```bash
bash Docker/simulate_accesses.sh
```
Default: writes **5** HTTP-scan lines for IP `203.0.113.7` to
`Docker/logs/access.log`.
Optional overrides:
```bash
bash Docker/simulate_accesses.sh <COUNT> <SOURCE_IP> <LOG_FILE>
# e.g. bash Docker/simulate_accesses.sh 6 198.51.100.5
```
Log line format:
```
YYYY-MM-DD HH:MM:SS bangui-access: http scan from <IP> "GET /.env HTTP/1.1" 404
```
### 2 — Verify the IP was banned
```bash
bash Docker/check_ban_status.sh
```
The `bangui-access` jail should appear alongside `bangui-sim`, showing the
banned IP and matched line count.
### 3 — Unban and re-test
```bash
bash Docker/check_ban_status.sh --unban 203.0.113.7
```
---
## Configuration Reference
| File | Purpose |
|------|---------|
| `fail2ban/filter.d/bangui-sim.conf` | Defines the `failregex` that matches simulation log lines |
| `fail2ban/jail.d/bangui-sim.conf` | Jail settings: `maxretry=3`, `bantime=60s`, `findtime=120s` |
| `Docker/logs/auth.log` | Log file written by the simulation script (host path) |
| `fail2ban/filter.d/bangui-access.conf` | Defines the `failregex` that matches access-scan log lines |
| `fail2ban/jail.d/bangui-access.conf` | Access jail settings: `maxretry=3`, `bantime=60s`, `findtime=120s` |
| `Docker/logs/access.log` | Log file written by `simulate_accesses.sh` (host path) |
Inside the container the log file is mounted at `/remotelogs/bangui/auth.log`
(see `fail2ban/paths-lsio.conf``remote_logs_path = /remotelogs`).
To change sensitivity, edit `fail2ban/jail.d/bangui-sim.conf`:
```ini
maxretry = 3 # failures before a ban
findtime = 120 # look-back window in seconds
bantime = 60 # ban duration in seconds
```
---
## Troubleshooting
### Log file not detected
The jail uses `backend = polling` for reliability inside Docker containers.
If fail2ban still does not pick up new lines, verify the volume mount in
`Docker/compose.debug.yml`:
```yaml
- ./logs:/remotelogs/bangui
```
and confirm `Docker/logs/auth.log` exists after running the simulation script.
### Filter regex mismatch
Test the regex manually:
```bash
docker exec bangui-fail2ban-dev \
fail2ban-regex /remotelogs/bangui/auth.log bangui-sim
docker exec bangui-fail2ban-dev \
fail2ban-regex /remotelogs/bangui/access.log bangui-access
```
The output should show matched lines. If nothing matches, check that the log
lines match the corresponding `failregex` pattern:
```
# bangui-sim (auth log):
YYYY-MM-DD HH:MM:SS bangui-auth: authentication failure from <IP>
# bangui-access (access log):
YYYY-MM-DD HH:MM:SS bangui-access: http scan from <IP> "<METHOD> <path> HTTP/1.1" <STATUS>
```
### iptables / permission errors
The fail2ban container requires `NET_ADMIN` and `NET_RAW` capabilities and
`network_mode: host`. Both are already set in `Docker/compose.debug.yml`. If
you see iptables errors, check that the host kernel has iptables loaded:
```bash
sudo modprobe ip_tables
```
### IP not banned despite enough failures
Check whether the source IP falls inside the `ignoreip` range defined in
`fail2ban/jail.d/bangui-sim.conf`:
```ini
ignoreip = 127.0.0.0/8 ::1 172.16.0.0/12
```
The default simulation IP `192.168.100.99` is outside these ranges and will be
banned normally.