# \ud83d\udee1\ufe0f ModGuard + Sentinel \u2014 Client Verification System
\nA **server plugin + client mod security system** that verifies legitimate clients and detects malicious modifications using a secure encrypted handshake \u2014 far more reliable than client-brand checks or simple mod name detection.<\/p>\n
\n
\n<\/p>\n
—<\/p>\n
## \ud83d\udce6 Components<\/p>\n
**\ud83d\udd0c ModGuard \u2014 Server Plugin**
\nSends encrypted challenges to connecting players, verifies responses, checks mod IDs against a blacklist, enforces a minimum Sentinel version, and optionally limits total installed mods. Supports cracked servers, Geyser\/Floodgate auto-bypass, configurable kick messages, player whitelist, and persistent mod history.<\/p>\n
**\ud83e\udde9 Sentinel \u2014 Client Mod**
\nInstalled by the player on their Fabric client. Receives the server challenge, collects the full mod list via FabricLoader, encrypts and returns it. Zero configuration. Zero performance impact.<\/p>\n
—<\/p>\n
## \u2699\ufe0f How It Works<\/p>\n
“`
\nPlayer joins
\n \u2192 Server sends encrypted challenge (RSA-2048 + nonce + HMAC-SHA256 secret)
\n \u2192 Sentinel collects mod list via FabricLoader
\n \u2192 Sentinel encrypts response (AES-256-GCM, key wrapped with RSA\/OAEP\/SHA-256)
\n \u2192 Server decrypts, verifies HMAC, checks protocol version + Sentinel version
\n \u2192 Mod list checked against blacklist and optional count limit
\n \u2192 Player approved or kicked with a configurable message
\n“`<\/p>\n
—<\/p>\n
## \ud83d\ude80 Installation<\/p>\n
**Server:**
\n1. Drop `ModGuard.jar` into `plugins\/`
\n2. Restart \u2014 `plugins\/ModGuard\/config.yml` and `modblacklist.json` are generated automatically<\/p>\n
**Client:** —<\/p>\n ## \ud83d\udd12 Security —<\/p>\n ## \ud83d\udeab Default Blacklisted Mods `meteor-client` \u00b7 `impact` \u00b7 `wurst` \u00b7 `liquidbounce` \u00b7 `aristois` \u00b7 `sigma` \u00b7 `thunderhack` \u00b7 `wolfram` \u00b7 `baritone` \u00b7 `freecam` \u00b7 `marlows-crystal-optimizer`<\/p>\n > Add or remove any mod ID via `\/modguard blacklist add —<\/p>\n ## \ud83d\udcbb Commands<\/p>\n Permission: `modguard.admin` (OP by default)<\/p>\n | Command | Description | —<\/p>\n ## \u2699\ufe0f Configuration “`yaml challenge-timeout-seconds: 15 # seconds client has to respond min-sentinel-version: “1.0.0” # kick players below this Sentinel version enable-mod-count-limit: false show-mod-list-in-console: true kick-messages: —<\/p>\n ## \ud83d\udccb Compatibility<\/p>\n | Scenario | Behavior | —<\/p>\n ## \ud83d\udd27 Requirements —<\/p>\n \ud83d\udcac **Join our Discord** for support, downloads, and updates A project that combines Mod+Plugin to detect and ban illegal mods,this also adds control what mods you wanna add\/remove from the list by adding using the ModiD<\/p>\n","protected":false},"featured_media":0,"template":"","meta":{"_minecraft_slug":"sentinel-for-modguard","_minecraft_project_id":"Qfq9Z8mH","_minecraft_author":"Treamhiler","_minecraft_license":"LicenseRef-All-Rights-Reserved","_minecraft_downloads":92,"_minecraft_follows":1,"_minecraft_client_side":"unsupported","_minecraft_server_side":"required","_minecraft_storage_type":"zip","_minecraft_archive_name":"sentinel-for-modguard.zip","_minecraft_size_bytes":142864,"_minecraft_version_count":10,"_minecraft_updated_at":"2026-05-15T19:52:14.937030Z","_minecraft_date_created":"2026-03-22T23:21:01.100705Z","_minecraft_date_modified":"2026-03-08T03:52:10.961639Z","_minecraft_project_url":"https:\/\/modrinth.com\/mod\/sentinel-for-modguard","_minecraft_icon_attachment_id":0,"_minecraft_imported_at":"2026-06-08T02:33:23+00:00","_minecraft_import_hash":"009ffc3779b86d8835dfbaea91f3152b","_minecraft_versions":"","_minecraft_links":"","_minecraft_gallery":"","_minecraft_api_metadata":""},"mod_category":[97,126,127,129,92],"mod_loader":[99,132,134],"minecraft_version":[62,37,40,41,73,74,38,78,79,80,81,82],"class_list":["post-137163","mod","type-mod","status-publish","hentry","mod_category-fabric","mod_category-management","mod_category-paper","mod_category-spigot","mod_category-utility","mod_loader-fabric","mod_loader-paper","mod_loader-spigot","minecraft_version-1-21","minecraft_version-1-21-1","minecraft_version-1-21-10","minecraft_version-1-21-11","minecraft_version-1-21-2","minecraft_version-1-21-3","minecraft_version-1-21-4","minecraft_version-1-21-5","minecraft_version-1-21-6","minecraft_version-1-21-7","minecraft_version-1-21-8","minecraft_version-1-21-9"],"yoast_head":"\n
\n1. Drop the correct `Sentinel-
\n2. Launch \u2014 no configuration needed<\/p>\n
\n– RSA-2048 keypair generated fresh per server session \u2014 never written to disk
\n– AES-256-GCM authenticated encryption \u2014 ciphertext is tamper-proof
\n– HMAC-SHA256 payload signing \u2014 server secret is never sent to the client
\n– Nonce included in every challenge \u2014 replay attacks are not possible
\n– Protocol version verified inside the encrypted payload \u2014 cannot be spoofed by a fake Sentinel
\n– Minimum Sentinel version enforcement \u2014 kick players running outdated client mods<\/p>\n
\nPre-seeded in `modblacklist.json` on first run:<\/p>\n
\n|—|—|
\n| `\/modguard blacklist
\n| `\/modguard whitelist
\n| `\/modguard mods
\n| `\/modguard check
\n| `\/modguard status` | Show online players, pending verifications, and plugin info |
\n| `\/modguard reload` | Reload configuration |<\/p>\n
\nFile: `plugins\/ModGuard\/config.yml`<\/p>\n
\noffline-mode: false # set true for cracked servers
\nallow-floodgate: true # Bedrock players via Geyser bypass verification<\/p>\n
\nchallenge-delay-ticks: 40 # delay before sending challenge after join<\/p>\n
\nprotocol-version: 1 # must match Sentinel \u2014 only change if you update both<\/p>\n
\nmax-mod-count: 50<\/p>\n
\nhighlight-banned-mods: true<\/p>\n
\n missing-sentinel: “&cSentinel mod is required to join this server.”
\n banned-mod: “&cAccess denied.”
\n outdated-sentinel: “&cYour Sentinel mod is outdated. Please update to &ev{version}&c.”
\n protocol-mismatch: “&cSentinel version mismatch. Please update your Sentinel mod.”
\n timeout: “&cVerification timed out.”
\n mod-count-exceeded: “&cToo many mods installed. Maximum allowed: &e{max}”
\n“`<\/p>\n
\n|—|—|
\n| Fabric client with Sentinel | Full verification |
\n| Vanilla client (no mods) | Handled automatically \u2014 no Sentinel required |
\n| Bedrock \/ Geyser | Bypassed automatically |
\n| Cracked \/ offline server | Supported via `offline-mode: true` |
\n| Forge \/ NeoForge | Not supported |
\n| Whitelisted player | Skips verification |<\/p>\n
\n– Paper \/ Spigot 1.21.x \u00b7 Java 21+
\n– Geyser + Floodgate *(optional, for Bedrock auto-bypass)*<\/p>\n
\n\ud83d\udd17 **More plugins by Treamhiler**
\n\ud83d\udc19 **GitHub**<\/p>\n","protected":false},"excerpt":{"rendered":"