# IPWL IP-Based Whitelist for Minecraft (Fabric) **Minecraft:** 1.21.1-26.2 | **Loader:** Fabric | **Java:** 25 | **License:** GPL A server-side mod that adds a second security layer on top of Mojang authentication. Every player is bound to one or more approved IP addresses, even if someone has a valid account, they cannot join unless they are connecting from a pre-approved IP. Connections are blocked before authentication even completes, so rejected players consume minimal server resources. --- ## Installation 1. Drop the `.jar` into your server's `mods/` folder. 2. Start the server. The mod creates `config/ipwl.json` automatically. 3. Add yourself as an IPWL admin (see below) and start managing players. > **No OP required.** IPWL uses its own admin list — OP status is completely separate. --- ## Admin Setup IPWL has its own permission system. Only players listed as IPWL admins can run any `/ipwl`, `/lockdown`, `/seen`, or `/connections` command. The server console always has full access. ``` /ipwl admin add — Grant IPWL access (saved to config immediately) /ipwl admin remove — Revoke access instantly, refreshes their command tree /ipwl admin list — Show all current IPWL admins ``` When an admin is removed they lose tab-complete and command execution immediately without needing to rejoin. --- ## Whitelist Commands ``` /ipwl add — Allow player from any IP /ipwl add — Allow player from a specific IP /ipwl addip — Add a second allowed IP to an existing player /ipwl removeip — Remove one specific IP from a player /ipwl remove — Remove player entirely and kick them if online /ipwl list — Show all whitelisted players and their IPs /ipwl reload — Reload config and whitelist from disk ``` **IP formats supported:** - Exact: `192.168.1.5` - Wildcard suffix: `192.168.1.*` (matches any IP starting with that prefix) - CIDR notation: `192.168.1.0/24` (works for both IPv4 and IPv6) - Any IP: `*` (player can join from anywhere) --- ## Temporary Access ``` /ipwl tempadd ``` Grants access for a limited time without modifying the permanent whitelist. Duration examples: `30m`, `2h`, `1d`, `3600s`. When the time expires, all online admins are notified automatically. --- ## IP Bans ``` /ipwl banip — Permanently ban an IP (blocks all accounts from it) /ipwl unbanip — Lift a permanent ban /ipwl banip list — Show all permanently banned IPs ``` Permanent bans are saved to `config/ipwl.json` and survive server restarts. --- ## Security Tools ``` /lockdown on — Block all new connections immediately (admins still allowed) /lockdown off — Resume normal operation /seen — Show last known IP and timestamp for a player /connections — List all currently active connections /security status — Show live security stats (blocked, allowed, temp bans, etc.) ``` --- ## Unknown Player Alerts When someone tries to join and is not on the whitelist, every online admin receives a chat message with two clickable buttons: - **[Accept]** — runs `/ipwl add ` instantly - **[Ban IP]** — runs `/ipwl banip ` instantly At the same time, the server console prints a clearly visible block: ``` [IPWL] ==================================================== [IPWL] !! UNKNOWN CONNECTION ATTEMPT !! [IPWL] ==================================================== [IPWL] Name : Steve [IPWL] IP : 192.168.1.100 [IPWL] To add : /ipwl add Steve 192.168.1.100 [IPWL] To ban : /ipwl banip 192.168.1.100 [IPWL] ==================================================== ``` All admin actions (accept, ban, remove) are broadcast to every online admin so no one acts on stale information. --- ## Bruteforce & Rate Limiting The mod automatically detects and blocks abusive connection patterns: | Pattern | Action | |---|---| | Same IP tries 3+ different usernames within 60 seconds | **1-hour ban** (bot / credential stuffing) | | Same IP hammers the server too fast (rate limit threshold) | **5-minute ban** (configurable) | | Permanent ban in config | Blocked forever | Both ban types are enforced before authentication completes. --- ## Logging ``` /ipwl logs verbose — Log all attempts, retries, and debug info /ipwl logs silent — Log only kicks and critical security events (default) ``` The console always shows unknown-player alerts and bruteforce detections regardless of log level. --- ## Configuration Located at `config/ipwl.json`. Created automatically on first run. | Field | Default | Description | |---|---|---| | `maxConnectionsPerIp` | `2` | Max simultaneous sessions from one IP | | `rateLimitWindowMs` | `1000` | Minimum ms between connections from same IP | | `maxFailuresBeforeTempBan` | `5` | Rate limit failures before 5-min temp ban | | `tempBanDurationMs` | `300000` | Single-name temp ban duration (ms) | | `enableRateLimit` | `true` | Toggle rate limiting | | `enableDuplicateCheck` | `true` | Block duplicate logins for the same username | | `enableJoinAlerts` | `true` | Send admin alerts for unknown players | | `alertCooldownMs` | `30000` | Minimum ms between alerts for the same IP | | `verboseLogging` | `false` | Mirrors `/ipwl logs verbose` | | `allowWildcardIps` | `true` | Allow `*` as a wildcard IP entry | | `allowSubnetPatterns` | `true` | Allow `192.168.1.*` style patterns | | `admins` | `[]` | List of IPWL admin usernames | | `bannedIps` | `[]` | Permanently banned IPs | --- ## Data Files | File | Contents | |---|---| | `config/ipwl.json` | All settings, admin list, permanent IP bans | | `config/ipwl_whitelist.json` | Player → IP mappings | | `config/ipwl-stats.json` | Persistent connection statistics (survives restarts) | | `config/ipwl-seen.json` | Last-seen data for `/seen` command | | `config/ipwl-lang.json` | Optional message overrides (no rebuild needed) | To customise any in-game message, create `config/ipwl-lang.json` on the server and add only the keys you want to change. This file takes priority over the built-in strings. --- ## How It Works (Brief) Every login attempt is intercepted at `ServerboundHelloPacket` — the very first packet a client sends — before Mojang authentication starts. The checks run in this order: 1. Lockdown mode → block non-admins 2. Permanent IP ban → block 3. Temp ban (rate limit or bruteforce escalation) → block 4. Bruteforce detection (3+ names from same IP in 60s) → 1-hour ban 5. Rate limit (too fast) → block, escalate to temp ban after threshold 6. Duplicate login check → block 7. Whitelist IP check → block + fire admin alert if not listed 8. Max connections per IP → block 9. Allow secondary async re-verification runs post-join as a safety net

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