Blocking the pesky Project Cars UDP broadcast leak

JJP

Formula 4 2nd Driver
Hello guys,

As many of you know, when Project Cars 2 (and 1?) UDP protocol is enabled, it may mess up online lobbies performances and stability.
My technical explanation is that it is partially due to the nature of UDP (LAN broadcast), and partially due to some weird PC2 netcode, which somehow pushes those UDP packets to the whole lobby over internet.

So today I created a firewall rule allowing UDP for the localhost (the PC you're gaming on), but blocking it from going "outside".
On my tests, it worked perfectly.
Once the rule enabled, UDP telemetry application running on my PC is OK, while a dashboard app running on my phone is KO (OK without the rule).

I need to give it a try in an actual lobby when we get a practice session, but I believe it would be best if others test it at the same time. Anyone interested, please follow this how-to.
Keep in mind that it will break connectivity with apps running on separate devices (such as smartphone dashboard apps). Unless they rely on a server app running on the PC (this is getting too technical ...) acting as a relay.

First you need to know your LAN subnet IP and mask ...
For most it should be 162.168.1.0/24 or something similar.
If you have no idea what I'm talking about, give a try to those links, ask Google, and if still too complicated, PM me.

Then, onto the rule.
On Windows, run "wf.msc". It should open the firewall interface. Create a new outgoing rule.
1617210565978.png


Configure the rule as follows :
Rule type = [Custom]
Program = [All programs] (or go find pCARS2AVX.exe if you really fancy)
Protocol and Ports = [Type : UDP] / [Local Port : All] / [Remote Port : Specific - 5606]
Scope = [Local IP : Add your subnet/mask here] / [Remote IP : Any]
Action = Block
Profile = tick everything
Name = whatever you want

Once created, the rule should appear in the list and be enabled by default.
 

TicklishPicklewickle

Moderator
Staff member
Moderator
PCARS Coordinator
Premium Member
Very neat!

I don't personally use any UDP apps while racing so I think I'll just keep it off but it could come in handy if I decide to run some apps that require UDP to be on.

This will definitely be useful for all those that do use an app that requires UDP.

Thanks for sharing the information @JJP :)
 

JJP

Formula 4 2nd Driver
You're welcome :)
If you never did, you may want to check pCars Profiler. A free and nice telemetry tool.
Both for telemetry recording analysis and live telemetry.
 

TicklishPicklewickle

Moderator
Staff member
Moderator
PCARS Coordinator
Premium Member
You're welcome :)
If you never did, you may want to check pCars Profiler. A free and nice telemetry tool.
Both for telemetry recording analysis and live telemetry.
I know pCars Profiler, I used it briefly for a couple races back in the PC1 days but never really felt like it was of that much use to me. I'm not really one for getting into the really small details in telemetry while I'm racing + I don't have a second screen to be able to monitor my telemetry live.
Occasionally if I want to really get into some detailed setup work I use RST Software (formerly known as PC2Tuner) which uses UDP. But I only use it in my offline practice which means I just turn UDP off when it's time to go online to race :)
 
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