ServerAddressSpaceFix

Fix the "unknown host" bug when adding a server or connecting directly to a server with a space at the end of the server address

by
147.8K Downloads
fabricoptimization
Configure a Compatible Minecraft Server

About this Mod

Note: This document was originally written in Chinese and translated to other languages by AI. If possible, I recommend reading the original Chinese document instead of a translated version.
简体中文(GitHub)     简体中文(Gitea)     English(GitHub)     English(Gitea)

Introduction

This mod is intended to fix a bug that was reported on November 26, 2021 and still has not been fixed.
Bug tracker link

Features

If the server address you enter on the "Add Server" or "Direct Connect" screen contains spaces at the beginning, the end, or in the middle, this mod will automatically remove them.
This prevents the "Unknown Host" bug mentioned above.

Why this mod exists
        A few months ago, I wanted to play on a server. I copied the address from the server's official website, pasted it into the "Server Address" field, saved it, and unexpectedly got an "Unknown Host" error.
        No panic, this was obviously DNS failing to resolve the corresponding address. Let's try pinging it first.
        Ping could resolve the domain name to an address, and then I suspected the Great Firewall might be doing something again, so I used a tool from ZhanZhangJia to test it. The results were exactly the same as mine.
        That was rather strange.
        Then, after fiddling with it for a while, I found the problem.
        There was a space at the end of the server address I copied.
        That was pretty hard to accept. After continuing to tinker for a while and confirming that the problem could be reproduced reliably, I submitted a bug report to the tracker.
        And guess what?
        The issue I filed on the bug tracker
        The comment below
        An earlier bug report
        My English is completely terrible, so I did not continue talking about it. The issue description was written using a translator.
        But honestly, I felt this was kind of absurd.
        Since your address is a String, how hard could it be to call trim on it afterwards?
        Also, as a player, when you tell me, "This was your own carelessness, so it does not even count as a bug," I cannot accept that.
        So, this mod was born.
    

Configuration file

  • If you have version isolation enabled, it should be located at .minecraft\versions\<version name>\config\ServerAddressSpaceFix.json5
  • If you do not have version isolation enabled, it should be located at .minecraft\config\ServerAddressSpaceFix.json5

This is just a regular JSON text file, except that JSON5 supports additional features such as comments.
All properties include comments, covering things such as functionality, value ranges, types, default values, and more.
You can edit it with a normal text editor.
You can even edit the configuration file while the game is running; it will be applied automatically after saving.

Known issues

All known issues have been fixed. If you find any new ones, please let me know.
If anyone is willing to help fix a bug, PRs are welcome ╰(°▽°)╯

License

I use the even more aggressive WTFPL than MIT.

Available Versions

ServerAddressSpaceFix 0.2.5release
MC 26.1, 26.1.1, 26.1.2, 26.2fabric
June 17, 2026
ServerAddressSpaceFix 0.2.4release
MC 26.1, 26.1.1, 26.1.2, 26.2fabric
June 17, 2026
ServerAddressSpaceFix 0.2.3release
MC 26.1, 26.1.1, 26.1.2fabric
June 4, 2026
ServerAddressSpaceFix 0.2.2release
MC 26.1, 26.1.1, 26.1.2fabric
March 26, 2026
ServerAddressSpaceFix 0.2.1release
MC 1.21, 1.21.1, 1.21.2, 1.21.3, 1.21.4, 1.21.5, 1.21.6, 1.21.7, 1.21.8, 1.21.9, 1.21.10, 1.21.11fabric
October 30, 2024

How to Install ServerAddressSpaceFix on Your Client

1

Install the Mod Loader Locally

Install fabric for your local Minecraft version.

2

Download the Matching File

Choose the ServerAddressSpaceFix file for fabric and Minecraft 26.2.

3

Install Mod

Place the .jar file in your local .minecraft/mods folder and restart Minecraft. No server-side installation is required.

Compatibility

Mod Loaders

fabric

Minecraft Versions

26.2, 26.1.2, 26.1.1 (+20 more)

Server-side

Unsupported

Recommended RAM

4 GB(min. 3 GB)

Frequently Asked Questions

Does ServerAddressSpaceFix need to be installed on the Minecraft server?

No. Modrinth marks ServerAddressSpaceFix as unsupported on the server side. Install it only in your local Minecraft mods folder. Your server can remain unchanged unless the mod page lists an additional dependency.

Which version and loader does ServerAddressSpaceFix require?

Use a file for fabric and your exact Minecraft version. Supported versions include 26.2, 26.1.2, 26.1.1. Files for different loaders are not interchangeable.

ServerAddressSpaceFix is not working – what should I check?

First check the Minecraft version, loader version and required dependencies. Put the .jar file in your local .minecraft/mods folder and remove older duplicates. Because this mod is client-side, adding server RAM will not fix it.

Minecraft Server for Your Group

ServerAddressSpaceFix stays on your client. Host a compatible world for your group.

Recommended RAM
4 GBfrom €5.2/mo
Minimum 3 GB | per 8 players
Create Server Now
Client Compatibility Guide
NVMe SSD Storage
DDoS Protection included

Details

License
Do What The F*ck You Want To Public License
Server-side
Unsupported

Supported Versions

26.226.1.226.1.126.11.21.111.21.101.21.91.21.81.21.71.21.6+13 more