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LAN sessions not working using steam

I am trying to develop a multiplayer game with blueprints to play with my friends, and i am using the shootout project and the new network tutorials as samples to set it up. After few attempts i managed to create, find and join sessions through steam and create, find and join sessions through LAN (with steam offline). The problem comes as i try to join a LAN session with steam online. The servers will show up in my server list but as soon as i try to join them nothing happens. I tried to debug and understand where the problem is and apparently the blueprint flow stops right at the join session node. I will paste here my defaultengine.ini file because my code looks ok and i think the problem may be there somewhere.



Product Version: UE 4.13
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asked Sep 20 '16 at 01:55 PM in Blueprint Scripting

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avatar image ImVawx ♦♦ STAFF Sep 20 '16 at 02:18 PM

Hey Marvash,

Can you verify that Steam is working for you? You can do this by running your game with Steam running. When you start, the Steam notification will pop up in the right hand corner.

If you do not see this, Steam isn't setup correctly. If that is the case, we can work towards fixing it. If Steam is setup correctly, there is also steps we can take to debug your issue and try to figure it out.


avatar image Marvash Sep 20 '16 at 02:50 PM

Thanks for the quick answer Kyle

Yes, steam works perfectly (except for the ping which is constantly 9999) i can see it pop up and i can create, find and join lobbies from wherever i want. The problem pops up when i create a lan session while steam is running in the background. The session will show in the server list but i just can't join it, the blueprint flow stops at the join session node (i figured it out by using some debug print strings).

avatar image ImVawx ♦♦ STAFF Sep 20 '16 at 02:57 PM

To start, the ping being 9999 is a known issue. You can see it here:


Secondly, are you trying to join a the Steam multiplayer game on the same computer that is running the host? As in, are you creating the game and trying to join it from the same computer on the same Steam account?


avatar image Marvash Sep 20 '16 at 03:01 PM

No, i am using two different computers on the same lan network with two different steam accounts.

avatar image ImVawx ♦♦ STAFF Sep 20 '16 at 03:22 PM

I am not seeing the same issue on my end. Can you post how you are joining the session after you have looked for it?

This is how I have my Blueprint setup:

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326075_bp.png (177.8 kB)
avatar image Marvash Sep 20 '16 at 03:43 PM

Ok here is my graph. All the variables are taken from my widgets (which i already checked thousands of times) and they are correct. The blueprint that you setted up has the lan disabled so the sessions will connect through steam but my issues comes up as both of those lan booleans are set to true.


joinsession.png (168.0 kB)
createsession.png (145.6 kB)
avatar image ImVawx ♦♦ STAFF Sep 20 '16 at 03:47 PM

What happens when you try to join a game with Steam on when LAN checkbox isn't checked?

avatar image Marvash Sep 20 '16 at 04:22 PM

when all the lan booleans are set to false (so when i am using steam) it works perfectly, i can see the sessions and join them with no problems.

avatar image Marvash Sep 20 '16 at 04:25 PM

the weird thing is that if i exit steam with both computers and i try to create a LAN session that will work. But if i am logged in steam with both computers and i create a LAN session the problem shows up.

avatar image Marvash Sep 20 '16 at 04:30 PM

To sum up: Offline with steam LAN session works, Steam session doesn't work (of course). Online with steam LAN session doesn't work (the problem shows up), Steam session works.

avatar image gon. May 03 '18 at 12:45 AM

Have exactly the same problem here. Any news or tips or trick or workaround to go over this or handle the situation? Is it possible to use OSS Null when LANCheckbox is true and SteamOSS when is false? Im using 4.18.3 and Advanced Sessions. Thank you.

avatar image Alfffffffffff Oct 16 '18 at 11:54 PM

any news on this one? i am having the exact same problem

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2 answers: sort voted first

Hey Mavash,

The checkbox for "Use LAN" will cause Steam to not behave correctly even if your two computers are on a LAN. This is because the Steam protocol for connecting players into multiplayer games relies on different methods than what the OnlineSubsystemNULL (or others) might do.

If you are creating multiplayer games and want to use Steam, you need to make sure that the "Use LAN" check boxes are set to false, through whatever method you deem fit. As in, a checkbox in a UI element, condition to see if the player is connected to Steam, etc...

Good luck with your project.

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answered Sep 20 '16 at 04:32 PM

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ImVawx ♦♦ STAFF
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avatar image Marvash Sep 20 '16 at 04:40 PM

So it is just not possible to join a LAN game with the steamsubsystem up and running did i get it right?

avatar image ImVawx ♦♦ STAFF Sep 20 '16 at 05:07 PM

The checkbox if "Use LAN" is simply for local area connections. Steam doesn't look at connections, even if they are in a LAN, in the same way. This means that if you have Use LAN checked, Steam isn't going to find those sessions as those sessions are flagged for LAN.

avatar image virtual_nomak Jun 27 '17 at 02:31 PM

Hi Kyle, I have the same issue and I've found your reply very helpful, anyhow how can I then find a LAN session if I'm connected to Steam? can I somehow switch to a different online subsystem (null) when checking in those options when I create or try to join a LAN match? I have seen many Steam games giving me the option to use LAN, so there must be a way.

avatar image Imagine-Games Sep 24 '17 at 07:22 PM

Kyle, the clients can find the LAN sessions using steam but they can not connect to them. But as Marvash said, if they exit steam and then create the LAN session than all clients are able to join. So trying to make a LAN game while steam is running will always fail. I am however not using the default Steam subsystem and instead the Advanced Steam one.... but just thought I would post because that is kinda of the workaround at the moment... turn off steam and lan will work (just gotta make sure the clients, and our actual game clients {the ones who buy the game} are aware of this... I will personally leave something in the UI explaining that)...

avatar image Marvash Sep 20 '16 at 05:14 PM

Alright now i understood! Thanks for the help and the support have a great day.

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gon, if you and all players exit steam (quit the program) it should work fine...

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answered May 03 '18 at 01:04 AM

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avatar image gon. May 03 '18 at 01:16 AM

Thnx RexVex for the answer. Yep, I checked that and it really works if I do that. What I ask is If nowdays we have a way to fix this or someone found a workaround or someone have a better idea than If LANCheckbox is unchecked on Create Advanced Sessions, disconnect from Steam or wake up OSS NULL to make LAN works and if LANCheckbox is checked, sleep OSS NULL and use OSS STEAM. Its an ugly fix to just force steam to be off or pop up a window asking clients and server to disconnect from Steam.

avatar image mightyenigma Jun 02 '18 at 04:59 PM

Wait, so I can do LAN and Steam on the same build of my game, and the user just has to turn off Steam and then LAN will work (as long as the LAN checkboxes are on/off?) But then if I want to support both, should I put my DefaultEngine.ini to have NULL or Steam as the OnlineSubsystem?

avatar image Nonlin Oct 26 '18 at 04:40 AM

Did you ever figure this out?

avatar image mightyenigma Oct 26 '18 at 06:03 PM

No I haven't done anything toward Steam yet, just got LAN working.

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