Garry's Mod

Overview

Release Date: November 29, 2006

Platform: PC (Steam, Linux servers supported)

Engine: Source Engine (Modified)

Scripting: Lua (100% customizable)

Max Players: 32+ (unlimited with resources)

System Requirements

Minimum

OS: Windows/Linux 32-bit or 64-bit
CPU: Pentium 4 3.0 GHz
RAM: 2GB minimum (4GB+)
Storage: 4GB SSD
Connection: 20Mbps upload

Installation Guide

1

Download Server Files

Use SteamCMD to download Garry's Mod dedicated server files

2

Add Addons

Place Workshop addons in garrysmod/addons directory

3

Configure Server

Create server.cfg and startup parameters

4

Launch Server

Run srcds.exe with appropriate game mode parameters

Server Configuration

// server.cfg (Garry's Mod)

hostname "My Gmod Server"

sv_password ""

rcon_password "AdminPass123"

sv_maxplayers 32

sv_gravity 600

sv_region 255

sv_alltalk 0

Common Bugs & Issues

Addon Load Errors

Addons fail to load due to missing dependencies or corrupt files. Check debug logs.

Lua Scripting Errors

Custom Lua scripts produce errors on player join. Enable developer mode.

FastDL Issues

Players download custom content slowly or fail. Configure FastDL properly.

Map Validation Failures

VPK or map files fail CRC check. Verify map integrity.

Troubleshooting

Server Crashes on Startup

Check for corrupted addons
Review console output for errors
Disable recently added addons
Update Garry's Mod to latest version

Players Cannot Connect

Check firewall and port forwarding
Verify STEAM_ID authentication
Check server console for connection errors
Restart server completely

Performance Optimization

Addon Optimization

Remove unused addons
Disable problematic Workshop addons
Use lightweight gamemodes
Monitor addon startup time

Server Settings

Reduce ticks_per_frame for better CPU usage
Optimize entity count limits
Lower max physics objects
Use Linux for better performance

Addon Development

Garry's Mod has the most extensive addon ecosystem with 10000+ community-created missions and gamemodes.

Popular Gamemodes

DarkRP, TTT, Prop Hunt, Murder, Wiremod

Development Tools

Hammer Editor, Lua scripting, Entity system

Advanced Troubleshooting

Lua Script Errors & Stack Traces

// Enable error logging
sv_logecho = 1
developer = 2

-- Comprehensive error handling
local status, err = pcall(function()
table.insert(nil, 1) -- Will error
end)
if not status then
print("Error: " .. err)
end

-- Stack trace generation
debug.traceback("Custom message")

Nil Table Access: Check table exists before indexing, use if tbl then pattern
Function Parameters: Validate argument types, use local copies for safety
Reference Cycles: Avoid circular table references, clean up metatable __gc handlers
Callback Crashes: Wrap callbacks in pcall(), verify entity/player still exists

Addon Loading & CRC Mismatch Resolution

-- Check addon loading status
for _, addon in ipairs(engine.GetAddons()) do
print("Addon: " .. addon.title .. " - " .. addon.status)
end

-- Verify gamemode dependencies
GAMEMODE = GAMEMODE or {}
if not gamemode.teamBased then
error("Gamemode missing: teamBased")
end

-- FastDL file validation
// Check server.cfg:
sv_downloadurl "http://fastdl.example.com/gmod/"
sv_allowdownload 1

CRC Mismatches: Clear client cache (steamapps/common/GarrysMod/garrysmod/cache), reinstall addon
Missing Addon Dependency: Check if parent addon properly subscribed/installed on all clients
Corrupted FastDL: Regenerate file list, ensure correct mime-types in web server
Version Conflicts: Run addon compatibility test, check Workshop for newer versions

Entity Networking & Datastream Debugging

-- Debug entity updates
function ENT:SendNetData()
  self:SetNWString("DebugData", "test")
  print("[" .. self:GetClass() .. "] Sync sent")
end

-- Receive net data safely
net.Receive("EventName", function(len, ply)
  if not ply or not ply:IsValid() then return end
  local data = net.ReadString()
end)

-- Monitor bandwidth
concommand.Add("net_debug", function()
  print("Entities networked: " .. #ents.GetAll())
end)

Desync Issues: Sync positions more frequently for player-controlled entities, use callbacks
Silent Failures: Wrap net receives with error checking, verify client receives callback
Bandwidth Limits: Reduce sync frequency for static entities, batch multiple updates
Entity Reference Stale: Always IsValid() check before using entities, cache entity tables safely

FastDL Server Configuration & Optimization

# nginx FastDL config example
server {
  listen 8080;
  root /var/www/gmod_fastdl;
  # Gzip for better compression
  gzip on;
  gzip_types application/* text/*;
  # Cache headers
  expires 7d;
}

# Generate file list
# Use create_addon.lua script or manual FTP upload

Slow Download Speeds: Check server bandwidth, enable gzip compression, use CDN
Missing Files: Verify all BSP materials/models uploaded, check file permissions (644)
MIME Type Errors: Configure .mdl/.vmt/.vtf MIME types in web server
Concurrent Connections: Limit per IP with nginx rate_limit, increase worker processes

Server Lag & Resource Profiling

-- Find expensive operations
local start = SysTime()
for i = 1, 10000 do
  local ent = Entity(i)
  if ent and ent:IsValid() then
    ent:GetPos() -- Actual work
  end
end
print("Took: " .. (SysTime() - start) * 1000 .. "ms")

-- Monitor server ConVars
sv_cheats = 0
developer = 2 -- More logging
sv_timeout 300 -- Disconnect timeout

Frame Rate Drops: Profile Think hooks, remove expensive loops in OnEntityCreated
Memory Bloat: Check for table references not cleared, use collectgarbage("collect")
Collision Issues: Reduce phantom collisions with SetSolid(SOLID_NONE), use OBB efficiently
Player Crashes: Server-side check for malformed net messages, validate all client input

Pro tip: Always wrap external function calls in pcall(). Use dedicated FastDL servers for large addons. Monitor console.log for silent errors.

Developer Resources

Lua API

Comprehensive Lua API with 3000+ functions for game customization

Gamemode Framework

DarkRP and other popular frameworks for rapid server development

Workshop Integration

One-click addon distribution via Steam Workshop to millions of players

FAQ

Why are my servers listed as LAN?

Set sv_region properly and ensure dedicated server is running. LAN shows only locally without proper setup.

How do I update addons automatically?

Use Workshop subscriptions and enable auto-update in server.cfg with workshop_autoupdate convar.