Module A3 · Operate & secure

DDoS, proxy, and networking basics

Owners ask the same three questions. Why can nobody join. Why does it lag under load. Why am I getting attacked. This lesson gives you the mental model. It also gives you a tiny resource that prints your live networking config, so the numbers stop being abstract. You will not become a network engineer. You will stop guessing and know what to check and what to ask your host.

You'll learn: Why your server is unreachable or laggy, what a proxy and filter actually do, and which ports matter.
Time: ~20 minutes.
You need: A server you can reach (local or VPS) and access to its firewall settings.
Path: Ports -> why connections fail -> what DDoS protection does -> when to use a proxy -> what hosting handles for you.

BEFORE YOU START

Build it

We are going to make the networking config concrete. This is a server-only resource. It reads your live network settings and prints them to the console. The ports, the OneSync mode, and the player cap stop being words in a guide and become numbers you can see. Follow the names exactly. Once it prints, the next section takes it apart and explains what each number controls.

Make the resource folder

The server has one folder for this lesson.

A resource is a folder of code FiveM loads. Inside your server's resources folder, create this folder:

code

resources/qu_networking_basics

Create the files

Every file named in the manifest exists.

Create this exact file layout:

code

resources/qu_networking_basics/
fxmanifest.lua
server.lua

Set the endpoints in server.cfg

The server binds TCP and UDP on the same port.

Open server.cfg. Near the top, where your other networking lines live, declare both endpoints on the same port:

code

endpoint_add_tcp "0.0.0.0:30120"
endpoint_add_udp "0.0.0.0:30120"
set qu_game_port 30120

0.0.0.0 means "listen on every network interface on this machine". 30120 is the port players connect to. The extra qu_game_port line is a convar, a setting outside your code that a script can read. This one is lesson-owned so the probe below can report the number. Keep it equal to the endpoint port. Cfx.re's default config binds both protocols, so allow both through the firewall.

Write fxmanifest.lua

FiveM knows which file to load.

fxmanifest.lua is the manifest file in every resource. It tells FiveM what the resource is and which files to load. Open it and paste this:

code

fx_version 'cerulean'
game 'gta5'

server_script 'server.lua'

cerulean is the current manifest format version. server_script tells FiveM this file runs on the server, not on players' machines.

Write the lesson code

The topic is now a runnable probe of your real config.

Open server.lua and paste this:

code

RegisterCommand('netinfo', function()
local port = GetConvarInt('qu_game_port', 0)
local maxClients = GetConvarInt('sv_maxClients', 48)
local oneSync = GetConvar('onesync', 'off')

print('[qu_networking_basics] game port (TCP+UDP): ' .. port)
print('[qu_networking_basics] txAdmin panel port: check txAdmin host settings (default 40120)')
print('[qu_networking_basics] sv_maxClients: ' .. maxClients)
print('[qu_networking_basics] onesync: ' .. oneSync)
end, true)

Start and test it

Your real networking numbers appear in the server console.

Add this line to server.cfg. ensure starts a resource and restarts it if it was already running:

code

ensure qu_networking_basics

Save, then run this in the txAdmin Live Console:

code

restart qu_networking_basics

Then run the test command in the same console:

code

netinfo

Your sv_maxClients and onesync values will be whatever your own server.cfg sets. The point is that they are now readable, not memorized.

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