AuthBack

Allows you play normally even when authentication servers are down

模组 Fabric 实用科技管理

介绍

中文介绍正在准备中，下面暂时显示原文。

Allows you to play as normal even when Mojang’s authentication servers are down.
Additionally also improves the networking behavior.

How does it work?

The responses from Mojang’s webservices/API are cached locally for some time.

If an outage occurs the previously cached responses are used.

For example this allows for your skin to be displayed properly.

Every client locally stores (or generates if not present) a keypair, which will be used as a fallback to authenticate with servers when Mojang’s authentication servers are down (see Public-key cryptography).

Please note:

The server also needs to have the mod installed
You must have already joined the server once (during the past 36 days)

The mod is optional for the client and server.

However if one side lacks the mod joining a server will be impossible when Mojang’s authentication servers/APIs are down.

Usage

Command

You can use the `/authback` command on servers with the mod to manage your public keys or those of other players if you are an admin.

Configuration

Client

You can configure the mod via

`Options > Online... > AuthBack...`
or if ModMenu is installed: `Mods > AuthBack > Click Icon/Settings`

General

The configuration is dynamically loaded from (sorted by highest priority)

Environment variables
prefixed with `AUTHBACK_<variant>`
where `variant is either SERVER OR CLIENT`
prefixed with `AUTHBACK_`
all properties are in UPPERCASE and use _ instead of . or -
System properties
prefixed with `authback.<variant>`
where `variant is either server OR client`
prefixed with `authback.`
A configuration file located in `.config/authback-<variant>.json`
where `variant is either server OR client`

Full list of configuration options

_Please note that the preconfigured values usually work out of the box.
_
_You should know exactly what you’re doing when doing modifications._

Common (Client and Server)

| Property | Type | Default | Notes |
| — | — | — | — |
| discovery-cache.default-reuse-minutes | int | 120 (2h) | The response for the discovery endpoint of Mojang’s API barely ever changes. This option instructs the mod to re-use the last saved response for the specified amount of minutes instead of contacting the API again. Using the cached response is a lot faster and saves network traffic during frequent game restarts. |
| global-public-keys-cache.default-reuse-minutes | int | 120 (2h) | Same as discovery-cache above but for global-public-keys. As of writing this documentation the keys were not changed in the past 3+ years. |
| game-profiles.delete-after-days | int | 36 | 36 days was choosen as the default because when a player changes their username the name will be unavailable for 37 days |
| game-profiles.max-cache-size | int | 250 | Maximum amount of game profiles to keep in the cache. If the size exceeds the maximum the oldest entries will be removed until the list is at 90% of the configured maximum. |
| username-to-id-resolver.use-vanilla | bool | false | Use the original/”vanilla” username-to-id resolver |
| username-to-id-resolver.expire-after-days | int | 36 | Days after which the cache entry will be deleted.
36 days was choosen as the default because when a player changes their username the name will be unavailable for 37 days.
The vanilla implementation uses 1 month. |
| username-to-id-resolver.refresh-before-expire-days | int | 14 | Days before the expiration when a cached entry will be refreshed when it’s accessed. |
| username-to-id-resolver.max-cache-size | int | 1000 | Maximum amount of usernames and ids to keep in the cache. If the size exceeds the maximum the oldest entries will be removed until the list is at 90% of the configured maximum. |
| username-to-id-resolver.resolve-offline-users-by-default | bool | true | Should offline users (e.g. unvalidated accounts) be cached?.
Please note

the offline-user cache is completely separated from the online-user cache and will never be persisted.
This is only the initial value
Clients will always resolve offline users and server will only do so when online-mode was disabled

|
| username-to-id-resolver.update-on-game-profile-fetch | bool | true | When a gameprofile is fetched: Should the information be relayed to the username-to-id-resolver/cache?
The cache will only be updated if required (e.g. unknown username/id or non-existing entry) |
| username-to-id-resolver.use-game-profile-cache | bool | true | Uses GameProfileCacheManager as secondary cache when all primary caches fail.
Usage should be extremely rare but can happen if the cache was e.g. corrupted |
| skip-extract-profile-action-types | bool | false | Debug-Option |

Server

Client

All client specific options can be changed / are described in the game options UI (see above).

FAQ

Where can I find my public key?

The public key can be found/copied under

`Options > Online... > AuthBack... > Key management`
or if ModMenu is installed: `Mods > AuthBack > Click Icon/Settings > Key management`

The authentification servers are down, I installed the mod on my server but I can’t join

This is because the server doesn’t know your public key.

You can fix this in the following way:

Make sure that you logged onto the server less than a month ago

that is because the entries in usercache.json – which will be used in such a case – will expire after a month

Make sure that you can run commands via the server console/RCON
Add the mod to your local client/game and launch it
and copy the public key from there (see above for details)
Then associate the public key on the server with your account:

/authback public_key add name <yourName> <yourPublicKey>
or /authback public_key add id <yourUUID> <yourPublicKey>

You should now be able to log in as usual.

Note however that profile related content like skins will not not be displayed.

It’s also recommended to restart the server once the outage is over to correctly load existing profiles.

The authentification servers are down, my friend got the mod but they can’t join my server

This is because they never joined with the mod before.

You can fix this in the following way if you are an Admin:

Tell your friend to launch the game with the mod
and to send their public key (see “Where can I find my public key?” above) to you
Associate the public key on the server with them by running /authback public_key add name <yourFriendsPlayerName> <yourFriendsPublicKey>

How can I test fallback authentication?

Ensure that the server knows your public key (you can check that on the server using /authback public_key list)
Ensure that fallback-auth.allow-always is enabled on the server (it should be enabled by default)
Start the client in offline mode
Enable Suppress any joinServer error in the client options
You should now be able to join the server using fallback authentication. Check the log for details.