This is NOT a complete in-depth guide of how a Local Server functions on a technical level.

This is a guide for people who just want to get a local server up and running to play with a couple buddies on Workshop maps or official maps.

Do not expect too many 'technical' solutions- most of our solutions involve fiddling around in the Console, Changing Game Options, whitelisting workshop mods, etc.

It is the nature of trying to use local servers while having a modded game.

Before we get started, in case you're new, forgot, or it's the main reason you're reading this guide;

Here's a quick rundown of how to swiftly create a Lobby in L4D2:

To open a Lobby click Play with Friends on a gamemode (Campaign, Realism, Mutation, Versus, Survival, Scavenger, etc) of your choosing.



Then below, click Create New Campaign Lobby.



You will now be in the Campaign Settings screen, where you can change the Campaign, Difficulty, Permissions for either a Public Lobby or Friend's Only Lobby, and finally, Server Type.



Remember to click on Server Type and change Official Dedicated to Local Server.

Then press Create Lobby.



Congrats! You have opened a lobby and it's assigned to be a Local Server. You can make any final adjustments within the lobby by clicking on Game Settings and it will bring you back to the previous screen.

You can change it back to public, change difficulties, change campaign, all that good stuff! Otherwise, everything else you see should be self-explanatory.

If that's all you're here for, then you do not need to read any further until you run into problems.

Note: When you press Game Settings in Lobby, you might see a new option below Server Type called Change Mode. What this does is allow you to change the game mode of your lobby from Campaign to a Mutation or other 4 Player-Lobby specific game modes.

A local server is a server type that a lobby leader can choose from the "Edit Game Settings" in the lobby's tab section. Something you've likely seen before.




Here we will briefly go over each server type that you can choose from:


Official Dedicated: Playing on an official Valve Server where the server is not affected by any cilent-side scripts or plugins and its the option most players prefer for servers as it usually chooses the most optimal location based on the lobby leader's location.
- These do NOT work with custom campaigns.

Best Available Dedicated: A Best Available Dedicated server is a non-official community server.
What this option does instead allows the game to choose between a community server and Valve's Servers. You do risk sometimes being brought to servers that have plugins/mods, but that is not always the case. This server type DOES work with custom campaigns. Use this option if you want to find community servers that run custom maps like Tank Playground or if you want to find a match quickly in general for vanilla maps as well.
Just know it will be entirely what the game chooses so you do not have a choice on if it will vanilla or with mods.
Not all custom campaigns will have a server available to them either.

Steam Group Server: In my experience, this is the least used server type out of them all.
What this is essentially does is once you select this as a server type in the game settings and you go back to the lobby to start the game, it will instead bring up a list of community/group servers you can choose from to join.
- This is, in my opinion, the least ideal server type you can choose from since the server list will not show you any servers currently running the campaign you currently have selected in the lobby (if it's a custom campaign as an example) and instead will be a list of vanilla campaigns with the occasional server running a custom map.

As for the last one...

A Local Server is essentially similar to playing the Single-Player campaign alone with bots or opening a map via console commands where all your workshop addons you've subscribed to, such as custom campaigns, workshop script changes, workshop plugins, custom models, custom weapons and all that goody stuff you have in your own personalised version of L4D2 will work without question.
Except now your friends- and strangers by that extent, can join to.

What it allows you to do is create your own dedicated server on your network that others can join that has everything you currently have installed in your own L4D2 game. As the server type points out though, its all local.

Meaning that you don't have to go looking for a community server if you want to play say...
Tank Playground with your friends as an example; With a Local Server, you won't have to play with other strangers (so long as you keep the lobby to friends only) nor be placed in a server that has plugins that radically shift and change up the game-play.

Why would you use a local server?

- You want a personal server but you don't want to go through the hassle of setting up a Dedicated Server for L4D2.

- You want to play L4D2 with your friends on custom campaigns but don't want to play on community servers.

- Want to play with your friends on official Campaigns, Versus, Mutations, etc; with your scripts/mods that you've downloaded such as; improved AI, Weapon Changes, Admin System, Scripts, etc;.

- If in rare cases, the official dedicated servers aren't finding good servers with good ping for you and your friends.

In general, I find that Local Servers are great if you just want to play L4D2 with friends and you all live semi close by to each other and you just want to play with your mods/scripts you've downloaded or if you're struggling to find servers with decent ping.

Other then that, I do NOT advise you use local servers outside of friend-only lobbies. I even suggest keeping local servers only for friend lobbies only because more often then not, it will just cause problems for randoms that join your server or who don't want to be playing off of your network. Most strangers are coming for the vanilla experience and they'd prefer to join games that have a consistent feel and don't want to randomly join into games with your epic buffs for the AWP.

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Note: The difference between a Local and Dedicated Server is that a Local Server is ran through the game itself, and may experience higher latency because the game itself is acting as a host.

A Dedicated Server is a separate application from the game and is either ran by Valve or a third party. It's far more stable because rather then running an entire game on top of server hosting,
its whole purpose is to connect players and process things that aren't related to running the actual game. Resulting in less lag.

Lag will still be an issue no matter what though, as if you try to connect to a Dedicated Server in; Lets say, Japan and you live in Germany, that distance creates latency, thus high ping.
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A Local Server does have some limitations on what you can do with it and I will be writing this from the perspective that you're hosting and the "rules" that come along with being the Host.

For starters, when you start a Local Server, a majority of workshop mods, since you're the Host, do not show up for other players.

Any custom model/re-textured weapons, survivors, infected, special infected, custom animations, custom sounds, etc will not show up for any other player, it's all client-side only.

That's why you're allowed to use your workshop mods in official servers.

Mods that will work globally in a local server are mainly workshop addons that actively affect the game play, such as V-Script mods, Weapon Changes, Improved Bots, to give a general idea.
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However, despite workshop models/re-skins not showing up on globally, they can still affect other players in your server and make the difference between if player can connect to your server at all.

Sometimes, these can prop as just occasional visual glitches on survivor models, longer loading times, or in a worst case scenario they may cause crashes and prevent players from joining.

So, for an exaggerated example, if you, the Host, have 100+ mods that graphically enhance the game and a friend connecting to your server is not subscribed to those same mods as you,
they will likely take longer to connect your server since the player connecting to your server technically has to temporarily "download" the workshop files to there own computer so they can join your server, despite the fact they will not see those changes themselves.

Most of the time though, if you have a reasonably sized mod list of custom survivor models, weapons, textures, etc and the person connecting has a decent computer and internet provider, this shouldn't matter in the majority of cases.

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But, Local Servers in general are weird. As a Host, workshop mods that change the model or textures of a survivor, weapon, props, textures, code, tend to be a-okay.

However, as a Host, the Local Server does not like any elaborate changes made specifically to the Infected & Special Infected. Any custom models and significant animation changes for the infected makes it difficult/impossible for others to join when you have these mods enabled unless they have it themselves.

I will note however that texture mods, insignificant [xdR] animations, and custom sounds for Special Infected tend to not cause any problems in my experience,
Do NOT use any workshop mods that alter the Common Infected in anyway when hosting a local server unless your friends agree to use them a well. It will make it impossible for anyone to connect to your server as a local server does not like it when the Common Infected are modified.

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As I mentioned briefly above, any custom models/reskins, whether it be for survivors, weapons, props, or addons with RNG-systems tend to not cause problems for other players, but there are some exceptions. Mainly, animation changes for Survivors and Weapons are generally a No-no as a host if you want to give those who connect a seamless experience.

Any direct animation changes to a Gun will cause, usually minor, visually harmless glitches and delays for those on your server. You won't notice these problems as they will only effect people who've connected to your server. [xdR] animations for Survivors may also cause some visual glitches on the client's end as well if they don't have the same as you.

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Other notes:
An obvious yet forgotten about limitation about a local server is that it is... local.
The server is ran on the Lobby Leader's Computer and if they tab out of the game for example, the entire server can freeze until they tab back in.

Other notes:

If the lobby leader's computer crashes, loses internet connection or leaves the game, the server is dead.

There is currently no existing way to change lobby leaders mid-game, you have to decide the leader before you get into the actual game.

Sv_Consistency 0 - This is the first thing you're going to want to do as the lobby leader, it makes it so that file consistency isn't a requirement for someone to join a server or to even start your server with your friends.

Note: While the command itself isn't a 'requirement', you might as well treat it as one. This will solve all issues revolving around consistency, so once you use this command you don't have to worry about that being the issue.

Stay away from workshop addons that change special infected models if you plan to play with friends.
- There are some custom models of special infected that do work even in a local server, but how well they work depends on the amount and the file size of this model itself. Meaning more often then not, reskins will work fine. But if you find that your friends are having trouble with connecting to your server, I advise turning off your addons for Special Infected.

In multiplayer settings change; "Custom Server Content" from "Allow All" to "None".


If we find any more fixes we'll add them here and if you're experiencing any problems with local servers, feel free to shoot a question here and we'll try to answer it the best we can if nothing above worked.












If all else fails, look into running a dedicated server ya lazy bastard.

This part is for sharing updated bits of information that I've recently learned and think would be fit to share. It's also a good place to look if you need find something feels "wrong" if you're playing on your friend's local server.

Its also a place where I needed to share extra information on local servers that I felt like I couldn't make there own dedicated section to. It will be small for now, but I will add to it overtime as I see fit.

• IMPORTANT: Over my time of playing on local severs with my friends, I've learned that ANY workshop/gun replacement models you get from the workshop can subtly change the statistics and the experience of other's on the server.
  
  
• While I can't explain how this happens, what I can say is that this only seems to effect the reload animations and grabbing animation (when the survivor holds out there hand to pick up an item) in how fast they reload or align with the original weapon's reload speeds. Sometimes, depending on the animation, it may straight up break the weapon's animation on other people's end when they try to reload or the reload time is "slower" and or slower then the original weapon's reload speed.
  
  
• The host won't notice these changes but anyone playing on his server could.
  Now granted, this is usually pretty avoidable by just not getting any weapon models that are DRASTICALLY different from the original model or are poorly animated.
  Also, If you're not experienced or are mindfully paying attention to how fast your weapon is reloading, you will likely not notice it for quite a while so it's nothing to be worried about.
  
  
• But I do suggest you keep it in mind before you subscribe to "Finger Guns" or anything of that sort if you play L4D2 with your friends often.

It's ridiculous this guide is the first result you'll get when you search up L4D2 Local Servers on Google. @_@[/strike]

Periodically I will add links to other guides here that I believe compliment this guide or give more detailed explanations on things you might like to know.
Thanks for reading!


https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3523589217

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2072453781

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=186498584