VIAaaS

VIAaaS - ViaVersion acetylsalicylic acid as a Service - Standalone ViaVersion proxy

How to use: server.example.com._p25565._v1_12_2._ofalse._uBACKUSERNAME.viaaas.example.com (similar to tor to web proxies)

Parts:

• server.example.com: backend server address
• _p: backend port
• _v: backend version (protocol id https://wiki.vg/Protocol_version_numbers or name with underline instead of dots). AUTO is default and 1.8 is fallback if it fails.
• _o: t to force online mode in frontend, f to disable online mode in frontend. If not set, it will be based on backend online mode.
• _u: username to use in backend connection
• viaaas.example.com: hostname suffix (defined in config)

Default Minecraft: viaaas.localhost with port 25565

Default WS URL: wss://localhost:25543/ws

• VIAaaS auth page is designed for storing accounts in the player's browser local storage. It requires a CORS Proxy for calling Mojang APIs, which may make Mojang see that as suspicious and reset/block your account password if the IP address is suspect.

• There are some information about Mojang password resetting: https://github.com/GeyserMC/Geyser/wiki/Common-Issues#mojang-resetting-account-credentials and https://mobile.twitter.com/MojangSupport/status/863697596350517248

• VIAaaS may have security vulnerabilities, make sure to block the ports in firewall and take care of browser local storage.

Download: https://github.com/ViaVersion/VIAaaS/actions (needs to be logged into GitHub)

Requires Java 11

How to start VIAaaS server:

• java -jar VIAaaS-all.jar

Usage for offline mode:

• Connect to mc.example.com.viaaas.localhost

Usage for online mode:

• You can use two accounts (avoids Bad Login error), the same account for front-end and back-end connections or use _of (offline mode in frontend, unencrypted).
• You should set up a CORS Proxy (something like https://www.npmjs.com/package/cors-anywhere, git clone https://github.com/Rob--W/cors-anywhere && cd cors-anywhere && npm install && node server.js) on the machine you are using the VIAaaS authenticator webpage. You can use my CORS Anywhere instance https://crp123-cors.herokuapp.com/ when using this page https://viaversion.github.io/VIAaaS/ but Mojang may see it as suspect.
• Go to VIAaaS auth webpage (https://localhost:25543/), configure the CORS Proxy URL (something like http://localhost:8080/, note the ending slash) and listen to the username A that you're using to connect to the proxy.
• Add the account B you'll use in _u(account B) parameter to browser auth page.
• Connect to mc.example.com._u(account B).viaaas.localhost (_u parameter can be removed if you are using the same username)
• Approve the login in auth webpage
• If you use the same online mode account, your client will give Bad Login after you approve it in your browser. You can use https://www.curseforge.com/minecraft/mc-mods/auth-me for reauthenticating the client.

WARNING

VIAaaS may trigger anti-cheats, due to block, item, movement and other differences between versions. USE AT OWN RISK

FAQ

VIAaaS is stuck when connecting with online mode:

• Your system may have low entropy, see https://wiki.archlinux.org/index.php/Rng-tools

My Microsoft account <18 years old is not able to log in, it's giving XSTS error:

• Add your account to a family (see https://wiki.vg/Microsoft_Authentication_Scheme#Authenticate_with_XSTS)

Why a online webpage for online mode?:

• It's easier to maintain in that way, because providing a chat with login requires encoding and decoding more packets which change through versions.
• It allows your account password and token to be kept with you