This is a detailed manual for the Slime Rancher MultiPlayer mod (SRMP), it has installation instructions, compability information, usage instructions, troubleshooting steps and some more. It is updated frequently to make it more readable and easier to understand. Now that it is on github, feel free to contribute! If this manual doesn't answer your questions or in case you don't understand something, feel free to ask your questions in [Saty's Discord](https://discord.gg/NtB7baV).
Slime Rancher MultiPlayer, or SRMP, is a mod developed by Saty that adds multiplayer functionality to the game Slime Rancher. Development was abandoned at one point but was recently picked up again by @Twirlbug.
SRMP works on all PC versions of the game except for the Microsoft Store version, so: Steam, Epic Games and GoG. Remember, this mod is for Slime Rancher 1, not 2! As Slime Rancher runs natively on windows, so will the mod. Both Slime Rancher and SRMP works on Linux, and the non-PC platform Mac, however getting Slime Rancher to work on those may require additional steps, and there are some issues with the mod that you may encounter (described in the Troubleshooting section). Below is a table to better visualize the platform compability for Slime Rancher + SRMP. Note: Table may currently be inaccurate as I don’t have enough data.
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🟡 Kinda works: So far only tested through Heroic Games Launcher as well as Lutris. I have had broken UI but that could likely be due to how bad my old setup was. Seems to have slightly worse performance than on Steam but it is likely not an issue with SRMP and that difference was pretty much eliminated for me after enabling virtual desktop.
🟡 Kinda works: I've only done minimal testing but from what the information I gathered there didn't seem to be any issues. Will still put this as Kinda works until I gather more data.
The first step is to download the mod. There are multiple ways to do this, and there are multiple versions to choose from so here is a short explanation. The first alternative: purchasing the mod on itch.io, which supports Saty. The second alternative is Discord, and the third alternative is Github. Do not get the mod from other sources. Before downloading, find out which version you need below.
There are many versions and two different “types” of the mod. The latest recommended version of the mod will probably always be the latest github release. If you are unsure, the latest recommended version as of me updating this manual is 1510.
There are two “types” for each version, one called SRML and one called Standalone. SRML is for the Slime Rancher Modlauncher, and allows you to use it with other mods (with varied results). Since that version is installed like any other SRML mod, instructions for that aren’t provided here. Usage instructions still apply. Standalone is for running SRMP standalone, that means indepentent of other modloaders, and it is actually really easy to install! That’s all you need to know for picking a version, if you are unsure, go with *SRMP_1510_Standalone*.
If you want to get the mod and support Saty at the same time, then head to the [itch.io page](https://satypardus.itch.io/slime-rancher-multiplayer-mod)! Here you pay and download your desired version. If you are new to this mod and didn’t read the ‘Which version to use?’ section above, I highly recommend you do so instead of downloading a random file and then bothering people in the discord with your questions. Note that new releases probably won't be published to itch. Now [install the mod](#install-the-mod).
The mod is available to download for free in [Saty's Discord](https://discord.gg/NtB7baV). All you need to do is join the discord and then download your desired version from the #multiplayer-development channel. So, now that you have downloaded your mod zip archive, move on to the next step, installation! This document includes instructions for [installing the mod](#install-the-mod).
The most obvious place to get the mod is probably from this github repo, head over to the [releases page](https://github.com/SatyPardus/srmp-public/releases) and get the version you have decided on. Then proceed to [install the mod](#install-the-mod).
Now that you have downloaded the mod it is time to install it. Remember that these instructions are for the Standalone version, SRML version is installed like other SRML mods and therefor instructions are not provided here. Troubleshooting tips may still apply to SRML version. Now follow the steps for your OS and platform.
<summary>1. Finding the game installation directory</summary>
The first step to installing the mod is to know where to install it to. We need to find the game installation directory (we will refer to it as GID from now on). This is done a little different depending on which platform (aka launcher) you have the game on. If you have it on multiple and one of them is steam, use steam. If you pirated the game, get out of my manual. Read the section for your launcher.
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<summary>1.a. Steam</summary>
It is really easy to find the GID on Steam, it only takes a few clicks. Open your library and find Slime Rancher in the list. Rightclick it, hover over ‘Manage’ and click ‘Browse local files’. This should open the explorer (or your default file explorer) in the GID. You know it is the correct directory if it contains a folder called SlimeRancher_Data.
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<summary>1.b. Epic Games</summary>
Finding the GID on Epic Games can be a little more complicated, as they aren’t installed to a universal location. The easiest thing is to initialize an install for another game and check what the pre-selected installation directory is, cancel the install and then check that directory for your GID. You know it is the correct directory if it contains a folder called SlimeRancher_Data. Another way to find it is to check the path of the Slime Rancher desktop entry/shortcut, or to just reinstall the game to a known location.
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<summary>1.c. GoG</summary>
Since I (the original manual author) have never used GoG, this is written using information I could find online. According to the GoG support center, games are installed to a universal directory by default, called ‘GoG Games’. This is located in a directory defined by the HOME environment variable. You should be able to find this path by opening command prompt and running the command ‘echo %HOME%’. You know it is the correct directory if it contains a folder called SlimeRancher_Data.
Once you know the GID (game installation directory) of your game you can move on to actually installing the mod. First up, make sure you have your GID open in a file explorer. Again the GID can be identified by containing a folder called SlimeRancher_Data. Next, open the directory containing the downloaded mod zip archive (probably Downloads). Copy or move the zip into the GID, not into SlimeRancher_Data or another folder inside of the GID, but the GID itself, the directory containing SlimeRancher_Data and such. Now that the zip archive is in place, extract it by rightclicking and selecting ‘extract here’. It should ask to replace a file in SlimeRancher_Data, if it does then select yes, if it doesn’t then you have extracted it to the wrong directory or you just need to move it out of a folder first. Once extracted correctly, it should have replaced a file in SlimeRancher_Data and created a new folder called Mods (do not put other mods in here). That’s it! Now move on to step 3.
Now to test if everything has installed correctly. Start the game from your launcher and wait for it to load. If installed correctly a console window will also open that probably takes focus from the game. Do not panic, this is a feature and the game is still running in another window. Once in the main menu, you should see a gray box in the top-right. If you do, you did everything correctly. If you don’t, try pressing f4 and if it still doesn’t show up then you did something wrong, go back. Now that you have the mod installed correctly, you can enter a username in the gray box, it can be anything and will be the name shown in-game. Now that the mod is installed and working you can move on to using the mod.
Find the game installation directory, extract the downloaded zip file into that directory replacing files inside. Done.
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<summary>1. Getting the game to run</summary>
In case you haven't already, it is strongly recommended to get the game running properly without issues before moving on to modding. I won't go into detail on how to do that here, but if you have it on steam then use proton. If you have it on Epic Games or GoG then use Lutris, Heroic Games Launcher or a similar solution. Tweak until it runs properly.
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<summary>2. Finding the game installation directory</summary>
This will be quite different depending on where you have the game.
For steam: find slime rancher in your library, right click 'Manage' > 'Browse local files'.
For other launchers, the paths may vary drastically. Most of them have an option to browse files though.
You know it's the correct directory if it contains another directory called "SlimeRancher_Data".
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<summary>3. Installing the mod</summary>
Once you know the GID (game installation directory) of your game you can move on to actually installing the mod. First up, make sure you have your GID open in a file explorer. Again the GID can be identified by containing a folder called SlimeRancher_Data. Next, open the directory containing the downloaded mod zip archive (probably Downloads). Copy or move the zip into the GID, not into SlimeRancher_Data or another folder inside of the GID, but the GID itself, the directory containing SlimeRancher_Data and such. Now that the zip archive is in place, extract it into this directory. It should replace a file in SlimeRancher_Data, if it does then select yes, if it doesn’t then you have extracted it to the wrong directory or you just need to move it out of a folder first. Once extracted correctly, it should have replaced a file in SlimeRancher_Data and created a new folder called Mods (do not put other mods in here). That’s it! Now move on to step 4.
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<summary>4. Verifying the install</summary>
Now to test if everything has installed correctly. Start the game from your launcher and wait for it to load. If installed correctly a console window will also open that probably takes focus from the game. Do not panic, this is a feature and the game is still running in another window. Once in the main menu, you should see a gray box in the top-right. If you do, you did everything correctly. If you don’t, try pressing f4 and if it still doesn’t show up then you did something wrong, go back. Now that you have the mod installed correctly, you can enter a username in the gray box, it can be anything and will be the name shown in-game. Now that the mod is installed and working you can move on to using the mod.
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Since this mod is all about multiplayer, here are some instructions for playing togheter. There are 3 main methods to choose from: Playing over LAN, Playing over “fake” LAN (VPN), and Playing over the Internet (port forwarding). The options are ranked below from easiest to hardest. There used to be a 4th method, server codes, but that method is currently not recommended and tend to cause more issues than it solves.
All three methods have a few things in common. First, make sure to choose a username if you haven’t already, this can be anything and will be the name shown in-game. Second, all three methods use some combination of IP address and port to host and join. An Ipv4 address which is the type you will most likely be using, looks like this: xxx.xxx.xxx.xxx, with x being numbers. Common ones for private IPs (local networks) are 192.168.x.xxx and 10.10.x.xxx. EG 192.168.1.43, 192.168.68.26 or 10.10.1.107. Public IPs (external/WAN connections) usually have completely different numbers but the structure is the same. The port is a combination of 5 numbers, which the host can find once they are in a loaded save.
This method only works if you and the other player/s are on the same local network (or same wifi, in incorrect terminology aka Layer 8 lingo). One player takes the role as the host. The host needs to load a save, it can be an old one or a new one it doesn’t matter just enter a save. Now in the game, the host checks the menu top right. There will be a few options there. Now the host notes down the port and clicks ‘Host’. The host now needs to find their local IP address. The fastest way to do this is probably through a terminal. On windows: open command prompt, enter ‘ipconfig’ (no ‘ signs) and press enter. Find the correct network adapter in the list and then the local ip. On linux, open a terminal and enter ‘ifconfig’, then do kinda the same thing as on windows. Players now from the main menu choose to join a game and join by IP address, entering it into the correct field, and then the port into the correct field and then joining. It’s that simple.
If you aren’t on the same network then there is still a pretty simple way to do it. Introducing, Hamachi! Before you get too exited you should know there is a drawback with this method, two actually. The first one is that you have to sign up for an account, the second one is that Hamachi has a rate limit, meaning that you could run into issues like not being able to see other players and falling through the map. Now the first step to using Hamachi is to getting an account (NOTE: these hamachi instructions are for Windows/Mac, if you are using linux you know better than to use hamachi but you still can, however it is through commandline so you won’t get any help here). You can create an account by going here. Once your account is created and verified and whatnot, download hamachi from their homepage. Now you need to setup and join a hamachi network, which is described pretty well here, skipping the ‘Host a Server’ section and the other game specific part at the end. Once all players are connected to the hamachi network, you just host and join as if you were on the same local network as described in the ‘Playing over LAN’ section above. If Hamachi fails you can try an alternative called Radmin. Hamachi local Ips may be different, if they are then google how to find them or something. I will update this to include instructions for that at some point.
The third and most advanced option is port forwarding, but it is also the one giving the best results if all players aren’t on the same network. There are two ways to port forward: via your router’s admin interface or through a UPnP portmapping client. The second one is easiest and most convenient, but not all routers support it, it could also pose a potential security risk. I would recommend trying UPnP first as it is pretty easy with the client I will be using, and try to do it via the admin interface if UPnP doesn’t work. Using a UPnP client doesn't make the security problems with UPnP bigger, because if it works then it is already enabled in your router which means the security flaws are already present.
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<summary>Via the router's admin interface</summary>
This method of port forwarding is the most complicated of the two, to be honest the UPnP client I used in those instructions isn’t even complicated at all so try that one first if you haven’t already. Now, to get started with this method you need login credentials for your router. They are usually found on a sticker on the back of the router. There might be one for wifi credentials and one for admin credentials so doublecheck that you have the right one. If you are lucky there is a default address listed on the sticker as well (usually called “internal address” or just “ipv4 address”) that will save you some time by skipping the next part of the instruction, finding your router’s local ip.
To find your router’s local ip on windows: open command prompt and run ‘ipconfig’. Look for something that says ‘default gateway’, that should be your router ip. On Linux: open a terminal and run ‘ip route’. The first thing that is displayed should be something like “default via 192.168.1.1”, that ip address at the end is the one you are looking for. On mac: open System Preferences, navigate to Network > Advanced > TCP/IP, and find the IP address listed next to “Router”, that is the one you are looking for.
Now that you have the IP of your router, open a web browser and put it into the address field (do not search for it, enter it as an address). It should open a webpage, if it doesn’t and just searches instead, put http:// in front of the address. Now log in with the credentials you found earlier, some routers display a default status page and requires you to press something before showing the login prompt. Once you are logged in try to find the port forwarding section, for me it was under “NAT/QoS”. Add a new rule. Below are the values you should input, each field might be called something different in your router and there might be extra fields, or less. Generally the other fields can be left empty, otherwise just google them. If you get confused, look up a video or image of port forwarding.
Application name: can be whatever, I will use ‘srmp’
Source net: can be left empty
Protocol: UDP
External start port: the port you noted down earlier
External end port: same as above
Internal port: same as above
IP Address: the IP of your machine (instructions on how to find in ‘Playing over LAN’)
Enable: yes
Now that the rule is complete, save and/or apply it. You should now be able to exit the admin interface of your router and test the rule. Host the save in the game if you haven’t already. Your friends join with your public IP and the port as described in the intro to this section. If you are unsure you can find your public IP at [https://whatismyipaddress.com](https://whatismyipaddress.com) or similar websites. No they don’t “doxx” you, your public IP address is just as the name suggests publically accessable and is necessary to access the internet. If you are using a VPN, turn it of as it "changes" your public IP to something where you can't map ports.
If you are lucky and your router supports UpnP and it is enabled this method will work for you. Using a special program you can utilize UPnP to create port forwards without having access to your router’s admin interface. To do this we will use a program called portmapper, download the .jar file from Assets [here](https://github.com/kaklakariada/portmapper/releases). You need to have java installed on your system. Once you have downloaded the jar file, run it and a window with a bunch of stuff will show up.
**1. Connect to your router.**
If you have a VPN active, deactivate it before continuing. It can cause issues with portmapping and multiplayer in general.
First you need to connect portmapper to your router, this will also tell you if your router has UPnP enabled or not.
Click the '*Connect*' button in the '*Router*' box. Give it a while.
If it works, you will see '*External address*' and '*Internal address*' change from '*(not connected)*' to an IP.
If it doesn't work, click '*PortMapper Settings...*' and change '*UPnP library*' to something else. NOTE: Don't set it to the dummy one.
If none of them worked, then UPnP isn't enabled in your router. The dummy option will always look like it works, but it's for testing and doesn't actually work.
**2. Create port mapping.**
Click '*Create*' in the '*Port mapping presets*' box. A new window will open.
In '*Description*', put whatever you want. I put srmp. NOTE: Illegal characters may cause issues on some routers.
The '*Remote host*' field can be left empty, but you can also put your friend's public IP for improved security. If you encounter issues later on, try emptying this field and do the next steps again.
For '*Internal Client*' check the '*Use local host*' button. It should select your local network IP, if not make sure you have vpn and tunnels disabled.
Now in the '*Ports*' box click the '*Add*' button.
Change Protol to UDP. Set both Internal and External port to the one you noted down earlier. If you didn't note down a port, set it to something like 16530 and change in the game later.
Now click '*Save*'. Then click '*Use*' in the '*Port mapping presets*' box.
**3. Hosting.**
Host with the port that you should know by know.
Your public IP by which other players will join can be found in portmapper (tends to be wrong), or with websites like [this](https://whatismyipaddress.com/).
You usually don't have to worry about removing these portmappings once you're done, as most routers do it on reboot.
If you want to remove or edit records, use the corresponding buttons in portmapper.
**4. Joining.**
Players join by the port that you either got or chose, and your public IP.
If it doesn't work and you put filled the '*Remote host*' field while creating the record: edit the record, clear that field, save it, and click the use button again.
If it doesn't work and that field is already empty, use a [port checker](https://portchecker.co) to determine if the port is open.
If it still doesn't work, make sure the external address in portmapper and the one found [here](https://whatismyipaddress.com/) are the same. If not, ask for assistance.
If you still need more help, ask for assistance in the discord.
NOTE: If this method didn't work and UPnP isn't enabled in your router, I don't recommend trying to enable it for future use. As this program demostrates, you don't need any form of authentication to map ports with UPnP. This means that rouge devices on your network could open ports which would allow hackers and other people with malicious intents to get full access to your home network. So if UPnP is disabled, leave it like that (unless you have a very sophisticated network architecture and you know what you're doing).
If you've opened the game after installing the mod then you have probably noticed that there is a black console window that opens after the game and steals focus.
This window can be quite handy for debugging, and can also be used to enter commands to manipulate the game. Below is a list of all currently available commands.
Here is a bunch of scenarios where some things with the mod might not work for different reasons, and how to solve those issues. Not all issues are listed here, and if this doesn’t help you, ask in the [Discord](https://discord.gg/NtB7baV). The main README file has an up-to-date list of known issues.
***Before driving yourself insane trying to find a solution to your problem***, if it's your first time starting an srmp session, get all players to restart the game entirely. This can fix some common issues. Restarting the game can also fix issues you may encounter later on.
If you are using Hamachi, Radmin or a similar solution then this is likely caused by rate limiting. The mod uses a lot of network traffic, especially when loading. One solution you could try is to disable encryption in Hamachi or whatever solution you are using, or if possible changing/removing any limits. If it doesn’t help immediately then wait a bit. If you have waited for a while and nothing has changed then you probably want to use another method in [using the mod](#using-the-mod). If you have tried everything up to port forwarding and it still doesn’t work then there is something on your network limiting your connection or your network/internet connection is just slow. Try to let someone else be the host.
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<summary>"Someone with that UUID already online"</summary>
This error is caused by an occupied UUID. If you are using a pirated version of the game, get out of this manual! If you aren’t and you still get the issue then open your game installation directory, find the userdata.json file in the SRMP folder and delete it. Restart the game.
This is a common connection error caused by players not having the same DLC activated. This can be solved by deactivating all DLCs or all players getting the same DLCs.
If you can’t connect to a server it is because something is blocking traffic. This could be because the selected port is already in use, there are firewall rules on the host/client machine blocking traffic, there are firewall rules on the router doing the same thing, incorrectly forwarded port etc.
This one is caused by connection issues. If you are using hamachi/radmin it is likely due to radmin. Disabling encryption may help. If you are trying to use server codes: don't. Just try to do things to improve your network connection. You can also let someone with a faster internet connection host.
This issue can be caused by the same things that case the "Players are invisible" issue. Try the fixes there. According to some user reports, walking around the map before hosting and letting other players join can also fix these issues.
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<summary>Game crashing instantly on startup</summary>
You probably did something wrong with installing the mod, like installing Standalone when you needed SRMP or the other way around. Or trying to install multiple versions on top of eachother. It is best to start with a fresh install of the game before installing the mod, and that includes clearing the installation directory before uninstalling it from your launcher.
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## Credits
Mainly wanted to include this section for people who want to ask me (the original manual author) questions.
