To set up a Garry’s Mod dedicated server in 2026, install SteamCMD, download the server with AppID 4020, create a Steam Game Server Login Token using Garry’s Mod AppID 4000, add +sv_setsteamaccount to your startup command, open UDP 27015, configure server.cfg, and load Workshop collections with +host_workshop_collection.

This guide takes you from zero to a stable launch: install with SteamCMD, create one Steam Game Server Login Token per server using Garry’s Mod AppID 4000, and use launch flags that control gamemode, map, players, and tickrate.

You will load Workshop collections cleanly, avoid the common “my addons don’t download” trap, and open the ports that actually matter. 

You will also learn what changed in 2026, so you only mount extra game content when a map, addon, voice line, music file, or excluded asset still needs it.

If your home network fights you, you will know when it’s time to move to bare-metal hosting with fast NVMe and high-clock CPUs.

Key Takeaways

• A GMod dedicated server runs as its own SRCDS process, so your world stays online when you close the game.
• Use SteamCMD with AppID 4020 to install and update your server on Windows or Linux.
• Prioritize strong single-thread CPU performance and NVMe storage. More cores alone won’t fix lag from heavy Lua, physics, entities, or bad addons.
• Use one valid GSLT per server instance with +sv_setsteamaccount. Create it with Garry’s Mod AppID 4000; servers without GSLT receive a severe server-list ranking penalty.
• Use a Workshop collection with +host_workshop_collection. You do not need a Steam Web API key for normal collection pulls.
• Server-side addon loading is not the same as client downloads. Use resource.AddWorkshop() for required Workshop assets or FastDL with sv_downloadurl for custom files.
• Open the right ports and fix NAT issues first. Most “server not showing” problems are GSLT, UDP 27015, firewall rules, sv_lan settings, server-browser delay, or CGNAT.
• Set tickrate based on tested load. Start around 66 for lighter servers and test 33 for heavy DarkRP or entity-heavy servers.
• Control entity spam with sane limits. One abusive player can create enough physics and networking load to hurt tick for everyone.
• Keep logs, back up config and data folders, and restart on crash or schedule for long-term uptime.
• Consider bare metal when tick drops, map changes drag, or VPS performance collapses at peak hours after you have already tested addons, entity limits, logs, and configs.

What Is a GMod Dedicated Server

A GMod dedicated server runs as a separate server process on your PC or a rented machine. It does not rely on your game client.

You start it with a launch command. It stays online even when you close Garry’s Mod.

That single difference changes everything:

• Friends can join any time
• You control rules, addons, and admin access in one place
• Your world stays consistent across sessions

Dedicated Server vs Listen Server

Dedicated Server

• Runs 24/7 if the machine stays on
• Keeps the same map, rules, and addons every restart
• Gives you clean admin control and predictable behavior

Listen Server

• Runs inside your game client
• Ends when you leave or crash
• Works for quick games with friends

When You Should Run One

Run dedicated if any of these are true:

• You host more than 6–10 players often
• You run DarkRP, TTT, big maps, or heavy Workshop packs
• Your group expects 24/7 uptime
• You want the same rules every time, not “whoever hosts decides”

If you want a server people return to, run dedicated.

Hosting Options That Match Your Goal

Your host sets the ceiling for performance, but config, addons, Lua quality, tickrate, and entity limits decide how much of that ceiling you actually use.

Option	Best For	Pros	Cons	Quick Advice
Self-Host At Home	Testing, private sessions	Free, fast to start	CGNAT can block inbound traffic, weak upload can hurt joins, port forwarding can be painful, and power cuts can break uptime	Great for learning. Risky for public uptime unless you have public IPv4, stable upload, port forwarding, and backup power.
VPS	Small communities, light addons	Cheap entry point, easy remote access	Shared CPU time, noisy neighbors, weak disk on budget plans	Pick high clock, NVMe, and a provider that does not oversell.
Dedicated Bare Metal	RP, mod-heavy servers, public communities	Predictable CPU time, strong disk I/O, better DDoS handling	Higher cost than VPS	Best fit for serious communities that need predictable CPU time, stronger disk I/O, and DDoS handling.

The Straight Advice On Hosting

If you want Garry’s Mod dedicated server hosting that stays smooth at peak hours, avoid crowded VPS plans with shared CPU time.

You want:

• High-clock CPU cores
• NVMe storage
• Real bandwidth with clean routing
• Support that can help with OS, network, firewall, and DDoS-layer issues

This is where a bare-metal provider like RedSwitches can fit if you need single-tenant CPU resources, NVMe options, strong network capacity, and infrastructure-level uptime coverage.

Practical GMod Server Requirements For 2026

GMod server performance often depends heavily on strong single-thread CPU performance, especially with Lua hooks, physics, and high entity counts.

CPU

Prioritize single-thread performance before core count.

• Pick a CPU with strong single-thread performance
• Treat “more cores” as secondary headroom, not the main goal
• Expect heavy RP servers to spike CPU during fights, spawns, and scripted events

Practical starting point:

• Light server: 2–4 strong cores
• Busy public server: start with 4–8 strong cores and high clock speed, then scale based on tick stability, addon load, and player count

RAM

RAM scales with players and addon bloat.

• Addons, maps, and gamemodes increase baseline memory
• Large servers spike RAM on map change and when Workshop content loads

Do this:

• Start at 8 GB for public servers
• Add more if you run big packs, RP frameworks, or lots of custom content

Storage

Use SSD at minimum.

• HDDs turn map changes into pain
• Workshop updates hammer slow disks

NVMe helps when:

• You restart often
• You load big maps
• You run large collections

Network

Low latency matters most for gameplay, while enough upload and clean routing matter for joins, downloads, and stable public access.

• Stable routing keeps hit registration and movement smooth
• Clean upload matters if you host from home

Home hosting warning:

• A weak upload link can choke joins, direct downloads, and live traffic, especially if you do not offload custom files through Workshop or FastDL
• CGNAT can block inbound connections even if you do everything “right”

A fast CPU core and fast disk usually matter more than extra cores for most GMod servers.

Install a GMod Dedicated Server With SteamCMD

SteamCMD gives you the official low-level install and update path. Use AppID 4020 for the dedicated server files.

Windows Install Clean Steps

1. Create two folders

• C:\steamcmd\
• C:\gmod_server\

2. Run SteamCMD once.  It will update itself. 

3. Install the server files
In the SteamCMD window, run:

force_install_dir “C:\gmod_server”

login anonymous

app_update 4020 validate

quit

 4. Confirm the install
  You should see the server files inside C:\gmod_server.

Linux Install Ubuntu And Debian

1. Install the 32-bit libraries SteamCMD needs 

sudo dpkg –add-architecture i386

sudo apt update

sudo apt install lib32gcc-s1 lib32stdc++6 curl tar

 2. Run the server as a non-root user

sudo useradd -m -s /bin/bash steam

sudo su – steam

3. Download and run SteamCMD, then install AppID 4020

mkdir -p ~/steamcmd && cd ~/steamcmd

curl -sL “https://steamcdn-a.akamaihd.net/client/installer/steamcmd_linux.tar.gz” | tar zxvf –

./steamcmd.sh +force_install_dir ~/gmod_server +login anonymous +app_update 4020 validate +quit

4. Confirm the install
Your server files should live in ~/gmod_server.

Keep SteamCMD For Updates

Client and server version mismatches can block joins. Update the server before deep troubleshooting.

Use this update flow:

• Stop the server
• Run app_update 4020 validate
• Start the server again

SteamCMD is the official install and update method you need to understand for a dedicated GMod server, even if your host wraps it in a control panel.

Make Your Server Show Up GSLT And Server Browser Basics

If you want a public server that avoids the severe no-token server-list penalty, you need a GSLT. Most “my server is not showing” reports start with GSLT, ports, firewall, NAT, or sv_lan issues.

What GSLT Does

A Game Server Login Token links your server instance to Steam. Create it with Garry’s Mod AppID 4000, not the dedicated server install AppID 4020.

• Steam assigns the server a game server account
• Your server avoids the severe no-token ranking penalty
• Your server still needs open ports, correct NAT, sv_lan 0, and a valid token to appear properly

Rules You Must Follow

Follow these or you will waste hours.

• Use one token per server instance
• Do not reuse a token across two servers
• If you reuse a token, the server may lose Steam connection and disconnect clients

Where To Place It

Put the token in your startup line.

• +sv_setsteamaccount <token>

Do not paste it into server.cfg. Put it in the launch command so it loads every boot.

No GSLT means a weaker public listing and a severe server-browser penalty.

Startup Scripts That Do Not Break

Your startup script controls the boot state. It decides your gamemode, map, players, Workshop collection, and Steam identity.

Windows Start Dot Bat Template

Create start.bat in your server root, next to srcds.exe.

@echo off

title GMod Dedicated Server

:restart

srcds.exe -console -game garrysmod +gamemode sandbox +map gm_construct +maxplayers 16 +sv_setsteamaccount YOUR_GSLT +host_workshop_collection YOUR_COLLECTION_ID

echo Server stopped or crashed. Restarting in 10 seconds…

timeout /t 10

goto restart

What this includes:

• -console for a visible server console
• -game garrysmod to run the right game
• +gamemode, +map, and +maxplayers so you boot into a playable state
• +sv_setsteamaccount so Steam lists the server
• +host_workshop_collection if you want the server to pull addons

Linux Start Dot Sh Template

Create start.sh in your server root, next to srcds_run.

#!/usr/bin/env bash

cd “$(dirname “$0″)”

while true; do

./srcds_run -game garrysmod -console +gamemode sandbox +map gm_construct +maxplayers 16 +sv_setsteamaccount YOUR_GSLT +host_workshop_collection YOUR_COLLECTION_ID

  echo “Server stopped or crashed. Restarting in 10 seconds…”

  sleep 10

done

Do this once:

chmod +x start.sh

Linux tips that prevent dumb failures:

• Always cd into the server directory before launch
• Keep paths simple
• Run as a non-root user

Do Not Copy Random Bat Files From Forums

Many “starter bat files” include junk flags, bad quoting, or outdated advice. You inherit problems you did not create.

Build your launch line yourself. Keep it short. Keep it readable.

Your launch line controls the boot state. Your long-term server behavior still belongs in server.cfg, gamemode configs, addon settings, and database-backed systems.

Basic server.cfg Template

Create or edit garrysmod/cfg/server.cfg, then add only the settings your server actually needs:hostname “My Garry’s Mod Server”
sv_password “”
rcon_password “CHANGE_THIS_LONG_RANDOM_PASSWORD”
sv_lan 0
sv_location “us”
sbox_maxprops 100
sbox_maxragdolls 5
sbox_maxnpcs 0
sv_allowdownload 1

Keep the GSLT out of server.cfg. Put +sv_setsteamaccount in your startup line.

Workshop Addons The Right Way

Workshop collections are the easiest official way to load public or unlisted addons on a dedicated server. They also cause the most confusion.

Use a Workshop Collection for Server-Side Addons

Create a Steam Workshop Collection, then put the collection ID in your launch line:

• +host_workshop_collection <collection_id>

Rules that matter:

• The collection must be Public or Unlisted
• Give Steam a few minutes to “see” a brand-new collection
• Keep your collection tight. Too many addons can cause long boot times, Lua errors, conflicts, and client download problems

Do You Need a Steam Web API Key for Workshop Collections?

For the standard +host_workshop_collection flow, use the collection ID. Current normal collection setup does not require a Steam Web API key.

Use the collection ID. Keep it simple.

When You Still Need Client Downloads

Server-side addons loading does not guarantee players have every required file. This is where people get missing textures, missing sounds, and error models.

You have three common paths:

Workshop Client Downloads

• You force required Workshop items to clients
• You use resource.AddWorkshop(“<workshop_id>”) in a server-side Lua file for required items
• Best when most assets already live on Workshop

FastDL

• You host custom assets on a web server
• You set sv_downloadurl “https://your-fastdl-domain/” in server.cfg
• Best for big custom packs, maps, and anything you do not want served from the game server

Direct Server Downloads

• The server sends files directly to clients
• It is slow and scales badly
• Avoid it for serious public servers because it is slower and harder to scale than Workshop or FastDL

Workshop collections load server addons. Client downloads still need resource.AddWorkshop(), FastDL, or another delivery path for required assets.

Ports And Firewall: What You Must Open

If players can’t connect, check ports, firewall, NAT, and CGNAT first. If your server doesn’t show, check GSLT, UDP 27015, sv_lan, firewall rules, and server-browser delay.

The Ports You Will See Most

These are the defaults you will run into on most installs:

• Server port: usually 27015 UDP for gameplay and query traffic; 27015 TCP only if you use RCON
• Client port: often 27005 UDP, but most server owners mainly forward the server port, usually UDP 27015
• SourceTV port: 27020 UDP if you use SourceTV

Important detail:

• If a port is already in use, your server may fail to bind correctly or use a different configured port.
• Check the server console output and set -port explicitly if you run multiple instances. Keep your firewall and router rules synced with the actual port.

Common Failure Causes

CGNAT from your ISP

• You forward ports correctly and it still fails
• You need a public IPv4 or a proper hosted server

Double NAT

• One router sits behind another router
• Your port forward hits the wrong device

Firewall rules missing for srcds.exe

• Windows blocks inbound or outbound traffic
• Allow srcds.exe in your firewall rules

Port collisions

• Another app already holds the default port
• Your server uses a different configured port and your router still forwards the old one

Most “server not showing” issues are GSLT, UDP 27015, firewall/NAT/CGNAT, sv_lan, invalid tokens, or server-browser delay.

Performance Tuning That Actually Works

Most GMod “lag” comes from three places:

• CPU time on the main thread
• Entity spam that explodes physics and networking
• Addons that fight each other or run heavy hooks every tick

Tickrate

Tickrate is how often the server simulates the world each second. Higher tickrate means more CPU work.

What tickrate changes:

• Movement and physics updates
• How often the server sends world state to clients
• How tight gameplay feels under load

When 66 makes sense:

• Sandbox with sane limits
• TTT, Murder, and most casual public servers
• You want responsive feel and you have a strong CPU core

When to drop to 33 for heavy RP:

• DarkRP servers with lots of players and scripted systems
• Big map + heavy job packs + constant spawns
• You see consistent tick drops during peak hours

Why high tickrate can crush CPU:

• Every extra tick multiplies work
• Addons do more per second
• Networking and entity packing cost rises fast

If you do not have headroom, do not chase 100 tick. For most communities, stable tick under peak load is more valuable than advertising a high tickrate that drops during fights or entity spikes.

Entity Limits And Sandbox Limits

High entity counts can degrade server performance. Physics props, ragdolls, and networked entities can make the problem worse.

Set limits that match your goal:

• Keep prop limits sane for your player cap
• Keep ragdolls low on public servers
• Restrict spam-prone tools and weapons

One abusive player can hurt the whole server:

• They spawn a wall of props
• Physics spikes
• Networking spikes
• Tick drops for every player

If you run a public Sandbox, limits are not optional. They are part of your uptime and moderation plan.

The Truth About sv_parallel_*

These settings are not magic switches.

• sv_parallel_sendsnapshot
• sv_parallel_packentities

Treat sv_parallel_* settings as advanced test-only changes. They may help some setups, but they can also create crashes, desync, or unstable behavior on others.

Test them carefully:

• Enable one at a time
• Load your real addon pack
• Stress test with players or bots
• Watch for weird crashes and desync

If you see random crashes, turn them off first.

Logs You Should Keep

Logs save time when your server breaks at 2 AM.

Keep logging for:

• Lua errors and stack traces
• Addon load failures
• Workshop download issues
• Repeated warnings that flood the console

Keep logs readable:

• Fix spammy errors instead of ignoring them
• Remove broken addons that throw errors every tick
• Use logs to narrow the exact addon that triggered a crash

Most lag is CPU time, entity spam, or addon bloat.

Admin Tools And Basic Security

A server without admin control becomes a lag machine. Security and moderation are part of performance.

RCON Basics

Set a strong rcon_password.

• Use a long password you do not reuse
• Do not share it in public channels

Do not expose RCON to the open internet without strict rules.

• Restrict access by firewall rules
• Use private management access where possible

RCON is powerful enough to damage your server configuration and player experience. Treat it like a privileged admin credential.

ULX And SAM

ULX is fine when:

• You want a proven admin stack
• You run small to mid servers
• You value familiarity and wide support

SAM may be a better pick when:

• You run larger communities
• You want a lighter admin layer
• You care about reducing addon overhead

Pick one. Do not pile admin systems on top of each other.

Simple Hard Rules

If you want a stable server, set hard rules.

• Limit who can spawn what
• Restrict toolgun abuse
• Lock down admin permissions
• Keep your addon set curated and reviewed

More addons does not mean a better server. It usually means more conflicts and more tick drops.

Admin control supports performance, moderation, and player trust.

Updating Backups And Uptime

Public servers often fail from repeatable ops mistakes: no backups, unsafe updates, weak monitoring, and untested addon changes. Treat updates and backups like part of your server, not a chore.

Update Workflow

Use the same loop every time.

• Stop the server cleanly
• Run SteamCMD update
• Start the server again

SteamCMD update command flow:

login anonymous

force_install_dir “YOUR_SERVER_PATH”

app_update 4020 validate

quit

Rules that save you pain:

• Update before you troubleshoot join issues
• Restart after updates even if the server “seems fine”
• Avoid updating mid-peak if you run a public community

What To Back Up

Back up what you can’t rebuild in 5 minutes.

Back up:

• garrysmod/cfg/ (server rules and core settings)
• garrysmod/settings/ (admins, users, permissions)
• garrysmod/data/ (many addons store progression here)

Also back up:

• Any gamemode config folders you edited
• Any database files or configs your RP stack depends on
• Custom maps and non-Workshop assets
• Anything that stores money, inventories, ranks, or playtime

Simple rule:

• If it affects player progression, back it up.

Auto Restart And Watchdog

Servers crash. Addons crash them faster. Plan for it.

Do two things:

• Restart on crash
• Restart on schedule

Restart on crash:

• Windows: a start.bat loop that relaunches srcds.exe
• Linux: a while true loop, or a systemd service with restart policy

Restart on schedule:

• A scheduled restart can reduce long-running memory issues and clear unstable states, but you should still fix addon errors and leaks
• Pick a quiet time for your region

A public server depends on both setup and operations. Installation gets it online; updates, backups, monitoring, and moderation keep it alive.

Troubleshooting Fast Diagnosis

Use this checklist before you reinstall anything. Most GMod server issues come from tokens, ports, Workshop settings, missing client downloads, or recent addon changes.

1. Server Not Listed

If your server does not appear in the browser, start with GSLT and ports. The most common causes are no GSLT, a bad token, a reused token, blocked ports, or LAN mode.

Add +sv_setsteamaccount to your startup line. Use one token per server instance. Restart the server. Confirm UDP 27015 is reachable from outside your network and make sure sv_lan is set to 0.

2. Can’t Connect From Outside LAN

If players can join locally but not from another network, check your network path first. CGNAT, double NAT, wrong router rules, or firewall blocks are usually the cause.

Test from a different network. Check whether your ISP uses CGNAT. Confirm your router forwards the correct port to the correct local IP. Allow srcds.exe through your firewall.

3. Workshop Not Loading

If Workshop addons do not load, check the collection before changing the server. The most common causes are a wrong collection ID, a private collection, Steam delay, or a bad launch line.

Confirm the collection ID in +host_workshop_collection. Set the collection to Public or Unlisted. Wait a few minutes after creating a new collection. Restart the server and check the console for Workshop errors.

4. Missing Textures Or ERROR Models

If players see missing textures, sounds, or ERROR models, the server may be loading addons without sending every required file to clients. Missing mounted content or broken FastDL paths can also cause this.

Confirm required items are forced to clients with resource.AddWorkshop(). If you use custom assets, set up FastDL with sv_downloadurl. Only mount extra game content if the missing asset still depends on excluded game content after the latest changes. Restart and retest with a fresh client join.

5. Random Crashes After Performance Tweaks

If crashes start after tuning, undo recent changes first. Unsafe cvars, unstable addon combinations, or sv_parallel settings are common triggers.

Revert recent performance changes. Disable sv_parallel_* if enabled. Remove the newest addon additions. Check logs for repeated Lua errors. Stress test in small stages instead of changing everything at once.

Fast Isolation Workflow

If the issue still does not make sense, use this order:

• Update the server with SteamCMD.
• Boot with a minimal addon set.
• Add addons back in small batches.
• Stop when crashes return.
• Isolate the last addon batch.

This is the fastest way to find the real cause without wasting hours on reinstalling a server that was not broken.

When to Upgrade to RedSwitches for Dedicated GMod Server Hosting

You can run GMod in many places, but weak CPU time, slow disks, and unstable routing can limit public server performance.

If tuning does not help after you isolate addons, reduce entity load, test configs, and verify logs, your host may be the bottleneck.

Signs Your Current Host Is Holding You Back

Watch for these signals:

• Tick drops the moment fights start or props stack up
• Map changes take forever, even on a “fresh” restart
• Players report stutter at peak hours, not just high ping
• You see random disconnects you can’t reproduce
• You deal with DDoS attempts or constant bot traffic
• Your VPS feels fast at night and terrible at prime time

If two or more happen weekly after addon and config testing, benchmark your host and consider moving to dedicated hardware.

What to Look For in a Dedicated Box for GMod Server Hosting

Your checklist should be simple:

• High clock CPU for strong single-thread performance
• NVMe storage for fast map loads and smoother Workshop churn
• Real bandwidth with clean routing and stable upload
• DDoS protection that can handle public server noise
• Fast provisioning so you can deploy and iterate quickly
• Support that can help with OS, network, firewall, and DDoS-layer issues without treating game traffic like generic web hosting

Why RedSwitches Fits This Upgrade

RedSwitches can fit GMod communities that need dedicated server hardware, NVMe options, strong network capacity, and infrastructure-level uptime coverage:

• Single-tenant bare metal CPU resources instead of shared VPS CPU scheduling
• NVMe options that can reduce map-load, restart, and Workshop update delays
• Network capacity suited to always-on public services, depending on selected location, bandwidth plan, and routing
• A path to upgrade CPU, RAM, storage, bandwidth, or location as player count and addon load grow

If you want stable dedicated GMod server hosting without fighting shared VPS limits, deploy your server on RedSwitches bare metal with NVMe and high-clock CPUs.

FAQs

Q. How Do I Fix Missing Textures In GMod?

Missing textures usually come from client download issues, broken Workshop items, FastDL problems, or assets that still depend on mounted Source game content.

Garry’s Mod now includes most Counter-Strike: Source content by default, so the old “CSS required” problem is smaller. You may still need extra mounted content if your map pack or addon uses excluded maps, voiceover, music, or specific referenced assets.

Quick test:

• Join your server.
• Load the maps you actually run.
• Check whether players see pink/black textures, missing sounds, or ERROR models.
• Confirm required Workshop items are forced with resource.AddWorkshop().
• Check FastDL paths if you use custom files.
• Only mount extra game content if the missing asset still depends on excluded Source content.

Q. Why Is My Server Not Showing In The Browser?

Most cases come down to a few common causes:

• No GSLT in your startup line
• Ports blocked by NAT, firewall, or ISP CGNAT
• Server-browser delay after a fresh restart

Fix steps that work:

• Add +sv_setsteamaccount <token> to your startup line
• Use one token per instance. Do not reuse a token across servers
• Open UDP 27015 to the machine running the server
• Allow srcds.exe through your firewall (inbound and outbound)

If you want an unlisted server:

• Use +hide_server 1 in the startup line

Q. Do I Need A Steam Web API Key For Workshop?

No. The standard +host_workshop_collection setup uses the collection ID and does not need a Steam Web API key.

Use this in your startup line:

• +host_workshop_collection <collection_id>

One important detail:

• A collection loads addons on the server
• It does not guarantee every client downloads every file

If players still see missing content:

• Force required Workshop items with resource.AddWorkshop() in a server-side Lua file
• Or use FastDL for large custom files

Q. What Tickrate Should I Use For DarkRP?

Use tickrate to keep the server stable, not to chase a number.

Good starting points:

• 33 tick for heavy DarkRP with lots of scripts, jobs, and entities
• 66 tick for lighter RP or smaller servers with a clean addon set

Rule that holds up:

• If your tick drops at peak hours, check CPU, entities, Lua errors, database calls, and addon load before blaming the network. Lower tickrate if the server lacks simulation headroom.

Q. Can I Host Multiple Servers On One Machine?

Yes, if you plan it right.

Do this:

• Run one instance per server folder
• Use a different port per instance and set each port explicitly to avoid conflicts
• Use one GSLT per instance

Expect limits:

• Each server still needs strong single-thread CPU performance
• Two busy servers on one box can perform worse than one well-resourced server if they compete for the same high-clock CPU cores, disk I/O, and network headroom

Q. What Ports Do I Open?

Start with the Source dedicated server defaults:

• 27015 UDP for gameplay and query traffic
• 27015 TCP only if you use RCON from outside your network
• 27020 UDP only if you run SourceTV

If you change your server port:

• Verify related ports such as RCON, SourceTV, client port, and Steam service traffic in logs and firewall rules
• Keep your router and firewall rules in sync with the actual port shown in your server logs