Add TCPShield / Proxy Protocol support

Adds enforced Proxy Protocol config and docs: a patch-set (config/patches/patch-set.json) that enables proxy protocol, whitelists TCPShield, and sets proxy/direct IPs; exposes PATCH_DEFINITIONS and mounts ./config/patches in docker-compose.yml; adds a featured "Proxy Protocol Support" entry to the dashboard mods page; and adds docs/tcpshield.md describing setup, verification, security model, and first-boot behavior.
This commit is contained in:
Aryan Singh committed 2026-07-11 18:51:27 -05:00
1 parent b043f03d28
commit dff2b5a9c4
4 files changed
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@@ -0,0 +1,42 @@
{
"patches": [
{
"file": "/data/config/proxy_protocol_support.json",
"file-format": "json",
"ops": [
{
"$set": {
"path": "$.enableProxyProtocol",
"value": true,
"value-type": "bool"
}
},
{
"$set": {
"path": "$.whitelistTCPShieldServers",
"value": true,
"value-type": "bool"
}
},
{
"$set": {
"path": "$.proxyServerIPs",
"value": ["127.0.0.1"]
}
},
{
"$set": {
"path": "$.directAccessIPs",
"value": [
"127.0.0.1",
"::1",
"10.0.0.0/8",
"172.16.0.0/12",
"192.168.0.0/16"
]
}
}
]
}
]
}
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@@ -59,6 +59,13 @@ const FEATURED = [
description:
"Pre-generates the world around spawn so nobody lags exploring new chunks. Run `chunky radius 2000` then `chunky start` in Console.",
},
{
slug: "proxy-protocol-support",
emoji: "🛡",
title: "Proxy Protocol Support",
description:
"Using TCPShield (or another proxy)? This restores players' real IPs so the Security page and IP bans work. Config is auto-enforced — see docs/tcpshield.md.",
},
];
export default function ModsPage() {
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@@ -45,6 +45,11 @@ services:
# Modpack support (leave empty for lean Fabric; see docs/mods-and-modpacks.md)
MODRINTH_MODPACK: ${MODRINTH_MODPACK:-}
# Enforce mod configs on every boot (proxy-protocol/TCPShield settings —
# see docs/tcpshield.md). Mods that rewrite their own config files can't
# clobber these: patches re-apply before each server start.
PATCH_DEFINITIONS: /patches/patch-set.json
TZ: ${TZ:-UTC}
ports:
- "${MC_PORT:-25565}:25565"
@@ -52,6 +57,7 @@ services:
- "${MAP_PORT:-8100}:8100"
volumes:
- ./data/mc:/data
- ./config/patches:/patches:ro
mem_limit: ${MC_CONTAINER_MEM_LIMIT:-7g}
# ── Scheduled world backups (itzg/mc-backup) ─────────────────────────────
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# TCPShield (DDoS protection + real player IPs)
[TCPShield](https://tcpshield.com) sits in front of the server: players connect to
your TCPShield domain, and your real server IP stays hidden and DDoS-protected.
The catch: without extra setup, every connection appears to come from TCPShield's
proxies, so the Security page, IP bans, and connection logs are useless.
TCPShield's own RealIP plugin is Bukkit/Bungee/Velocity-only — it does not exist
for Fabric. The working path for this stack is **PROXY protocol v2** plus the
**Proxy Protocol Support** Fabric mod.
## Setup
1. **TCPShield panel** → your backend → enable **Proxy Protocol**.
2. **Mods page** → Recommended → add **Proxy Protocol Support** → Apply
(or append `proxy-protocol-support` to `MODRINTH_PROJECTS` in `.env` and
`docker compose up -d mc`).
3. Nothing else — the mod's configuration is **enforced automatically on every
boot** by `config/patches/patch-set.json` (see below). Restart once after
installing so the patch applies:
```bash
docker compose restart mc
```
## Verifying it works
Watch the startup log (`docker compose logs -f mc`). You must see all three:
```
Proxy Protocol Support is enabled!
TCPShield integration enabled! Fetching official IPs...
Successfully added 2 TCPShield IPs to the trusted proxy list.
```
Then join through your TCPShield domain — the console shows your **real IP**, and
`docker compose ps` shows `mc` **healthy**.
## How the config is managed (don't hand-edit!)
The mod rewrites `config/proxy_protocol_support.json` at every startup, which
silently clobbers hand edits. Instead, the server image applies
`config/patches/patch-set.json` from this repo **before every server start**,
enforcing:
| Setting | Value | Why |
|---|---|---|
| `enableProxyProtocol` | `true` | decode PROXY protocol headers |
| `whitelistTCPShieldServers` | `true` | auto-fetch TCPShield's proxy IP ranges — no hardcoding, survives their infra changes |
| `proxyServerIPs` | `127.0.0.1` | (TCPShield's ranges are added automatically at runtime) |
| `directAccessIPs` | localhost (`127.0.0.1`, `::1`) + private ranges (`10/8`, `172.16/12`, `192.168/16`) | container healthcheck + LAN/panel access |
To change a value, edit the patch file in the repo and `docker compose up -d mc`.
**First-boot note:** on a brand-new install the mod's config file doesn't exist
yet when patches run, so the very first boot uses mod defaults; every boot after
that is patched. One `docker compose restart mc` after first install settles it.
## Security model
PROXY protocol headers carry no signature, so anyone who finds your raw server IP
could spoof client IPs — the mod prevents this with default-deny:
- PROXY headers are only accepted from **TCPShield's published ranges** (auto-fetched)
- Direct, header-less connections are only accepted from **localhost + LAN**
- Everything else → `REJECTED unauthorized direct connection` in the log
So occasional `REJECTED` lines from random public IPs are the wall working —
that's scanner bots hitting your raw IP and bouncing. A `REJECTED ... /0:0:0:0:0:0:0:1`
(IPv6 localhost) every few seconds means the container healthcheck is being
blocked — that's exactly what the `::1` entry in the patch prevents; if you see
it, the patch didn't apply (check `docker compose logs mc | head -50`).
For belt-and-braces, also enable TCPShield's Advanced Firewall (panel → Network →
Firewall), and consider host-firewalling port 25565 to TCPShield's ranges
(`curl tcpshield.com/v4`) once everything works.
## Gotchas
- **Friends must connect via the TCPShield domain** — direct-IP connections from
outside your LAN are rejected by design once this is active.
- If real players start bouncing with `REJECTED`, TCPShield may have changed
their IP ranges *and* the auto-fetch failed at boot — restart the server so it
re-fetches.