How to Fix The LAN Play in 2025

This guide will teach you how to change your preferred network interface.

Why It's Problematic ?

Flawed Design

Borderlands: TSE only binds to your default network interface instead of all available ones which in "some cases" is not desirable and changing their priority through metrics won't help with that either.

This design flaw will prevent you from playing with friends using the LAN play feature if you have a complicated network stack for all kinds of stuff like virtual machines, bridges, multiple connections, VPNs etc.

Steps Explaining The Problem

1. Game Sends UDP Packets From The Port 14001 to Everywhere (255.255.255.255).
   
2. If The Port 14001 Is Blocked, 7777 Is Used For Broadcast Instead.
   
3. A Two Way Handshake Is Made and Client Displays Status of The Host In The Browser.
   
4. Client Tries to Connect to The Host Using The UDP Port 7777 But Via Wrong Source and Destination IP Address.
   
5. Game Will Give Up On Connection Attempts and Drop It After 30 Seconds.
   

How to Fix It ?

-multihome=IP_ADDRESS

We're gonna use a really simple solution to bind the game to our new network interface. This fix applies to all operating systems including Linux.

Both clients and hosts need to follow the same steps.

(For educational purposes only)

Linux

Steam

1. Open up your terminal emulator.
   
2. Type ip addr and find your desired network interface you want to play with like ZeroTier.
   
3. Copy your IPv4 address.
   
4. Select the Borderlands: The Pre-Sequel in your steam library and right click to it.
   
5. Click onto Properties below the drop-down menu.
   
6. Find the LAUNCH OPTIONS and type the following:
   -multihome=PUT_YOUR_IP_HERE
   Sample: -multihome=10.143.65.1
   
7. Launch the game.
   
8. Press the N key and select the LAN option.
   
9. Let your friend join your game or browse your friend's game through the browser.
   
10. If broadcast is reachable you or your friend should be able to see the host.

Extra Steps for People Using ZeroTier

ZeroTier doesn't allow broadcast messages to pass through on Linux by default to prevent breakage. Most games are fine with that but Borderlands: TSE requires it no matter what for LAN play.

1. Open up your terminal emulator.
   
2. Gain root access by typing su, sudo su or doas su.
   
3. Make sure you're connected to the ZeroTier.
   
4. Type route and find your desired interface.
   
5. Type the following replacing the interface with yours:
   route add -host 255.255.255.255 dev PUT_IFACE_HERE
   Sample: route add -host 255.255.255.255 dev ztly1bb7fn
   
6. You might want to add broadcasting routes in your ZeroTier network using the web panel but they're ignored on Linux. You can follow these guide for that: Enable Broadcasting for your Zerotier Network in the Dashboard[github.com] (Note that I haven't tested not using them in my experiments, ZeroTier already has a broadcasting ticking box for each network, this step might be removed)
   
7. You're good to go and your game should be discoverable by your friends in your network.

Lutris

1. Open up your terminal emulator.
   
2. Type ip addr and find your desired network interface you want to play with like ZeroTier.
   
3. Copy your IPv4 address.
   
4. Right click onto your game and select the Configure option .
   
5. Go into Game options above.
   
6. Find the Arguments section below and type the following:
   -multihome=PUT_YOUR_IP_HERE
   Sample: -multihome=10.143.65.1
   
7. Launch the game.
   
8. Press the N key and select the LAN option.
   
9. Let your friend join your game or browse your friend's game through the browser.
   
10. If broadcast is reachable you or your friend should be able to see the host.

Extra Steps for People Using ZeroTier

ZeroTier doesn't allow broadcast messages to pass through on Linux by default to prevent breakage. Most games are fine with that but Borderlands: TSE requires it no matter what for LAN play.

1. Open up your terminal emulator.
   
2. Gain root access by typing su, sudo su or doas su.
   
3. Make sure you're connected to the ZeroTier.
   
4. Type route and find your desired interface.
   
5. Type the following replacing the interface with yours:
   route add -host 255.255.255.255 dev PUT_IFACE_HERE
   Sample: route add -host 255.255.255.255 dev ztly1bb7fn
   
6. You might want to add broadcasting routes in your ZeroTier network using the web panel but they're ignored on Linux. You can follow these guide for that: Enable Broadcasting for your Zerotier Network in the Dashboard[github.com] (Note that I haven't tested not using them in my experiments, ZeroTier already has a broadcasting ticking box for each network, this step might be removed)
   
7. You're good to go and your game should be discoverable by your friends in your network.

If you done everything correctly then your interface should be able to do broadcast with the right IP address and let others discover your game.

Windows

Steam

1. Open up your powershell.
   
2. Type ipconfig and find your desired network interface you want to play with like ZeroTier.
   
3. Copy your IPv4 address.
   
4. Select the Borderlands: The Pre-Sequel in your steam library and right click to it.
   
5. Click onto Properties below the drop-down menu.
   
6. Find the LAUNCH OPTIONS and type the following:
   -multihome=PUT_YOUR_IP_HERE
   Sample: -multihome=10.143.65.1
   
7. Launch the game.
   
8. Press the N key and select the LAN option.
   
9. Let your friend join your game or browse your friend's game through the browser.
   
10. If broadcast is reachable you or your friend should be able to see the host.

Epic Games

1. Open up your powershell.
   
2. Type ipconfig and find your desired network interface you want to play with like ZeroTier.
   
3. Copy your IPv4 address.
   
4. Go into your account settings and select the Borderlands: The Pre-Sequel.
   
5. Click onto Additional Command Line Arguments below the drop-down menu.
   
6. Find the Blank Space and type the following:
   -multihome=PUT_YOUR_IP_HERE
   Sample: -multihome=10.143.65.1
   
7. Exit the settings and launch the game.
   
8. Press the N key and select the LAN option.
   
9. Let your friend join your game or browse your friend's game through the browser.
   
10. If broadcast is reachable you or your friend should be able to see the host.

Non-Standard Platform or Different Launcher

1. Open up your powershell.
   
2. Type ipconfig and find your desired network interface you want to play with like ZeroTier.
   
3. Copy your IPv4 address.
   
4. Right click on your game's shortcut.
   
5. Click onto Properties below the drop-down menu
   
6. Find the Target: section and get to the end of the line by using the End key or Arrow Keys or by moving your mouse.
   
7. Add one character space by pressing your spacebar once and type the following:
   -multihome=PUT_YOUR_IP_HERE
   Sample:
   "C:\Engi\BroderlandsTSE\Binaries\Win32\BorderlandsTSE.exe" -multihome=10.143.65.1
   
8. Exit the properties and launch the game.
   
9. Press the N key and select the LAN option.
   
10. Let your friend join your game or browse your friend's game through the browser.
    
11. If broadcast is reachable you or your friend should be able to see the host.

Things To Keep In Mind

Set The Correct Firewall Rules

If the UDP port 7777 is not reachable and you haven't allowed access for Borderlands: The Pre-Sequel you can't play with your friends using LAN.

Windows

You're usually gonna have a pop up like that saying if you want allow inbound access from Borderlands: TSE, you need to to check the both ticks for greater compatibility.

If you somehow cleared the both ticks/forgot to tick the other one and applied the settings and your friend cannot connect to your game despite following the right steps then you have to re-enable the inbound traffic for the game using the control panel. Follow these standard steps to go into your defender firewall:
After clicking the Change Settings button you'll gain admin access to your firewall rules.
Find your game either by scrolling or typing it carefully then check the both boxes saying Private and Public and save by pressing OK below. Any inbound port your game uses should now be open, be sure to select the right game. If you're unsure click onto Details and check the location of the program.

Linux

Most Linux distributions don't come with a pre-configured firewall rules so you're often don't need to change anything but if they do in your case then you first need to check your startup services.
If you're using SystemD you can use this command to see if you have firewalld or ufw installed:

systemctl --type=service

or using OpenRC

rc-update

It's safe to disable them or clear your firewall rules as long as you're behind a NAT but if you want to keep using them you need to allow these two UDP ports: 14001 & 7777.

I won't be covering the ideal ways to add firewall rules but you can use these commands to allow the required ports:

(Gain root access before applying them)

For UFW:

ufw allow 7777/udp
ufw allow 14001/udp

For firewalld:

Get the zone name you want to apply:

firewall-cmd --get-active-zones

Apply the rules:

firewall-cmd --permanent --zone=ZONE_NAME_HERE --add-port=7777/udp
firewall-cmd --permanent --zone=ZONE_NAME_HERE --add-port=14001/udp

Any inbound port your game uses should now be open.

An active game session looks like this:

Different Game Versions

Different versions of the game cannot join each other, this is especially true for Linux and Mac versions since they don't receive the same care Windows version receives, make sure to check your multiplayer version and use the proton compatibility layer for now.

Have All The DLCs

You can happily play the base game with your friend but if you don't share the same DLCs then you won't be able to travel to their corresponding maps with them or if they're already playing on a DLC map then you won't be able to join at all.

Thanks for Reading My Guide

:33