My LAN server won't let my cousin join me or me join my cousin. It won't show up on the multiplayer screen - it keeps saying "scanning for LAN servers" but it never finds it. I am at his house and we use different computers but it won't connect. How can I fix this?
A few problems that can arise when attempting to connect a game. Note that these suggestions are made to minimize issues, I do not mean to imply you have to meet every condition here for it to work. Also I am assuming a LAN game, since non-LAN games introduce a whole host of other issues to resolve.
Lack of connectivity ensure everyone is connected to the home LAN (WiFi or cable), free WiFi or someone else's open WiFi can cause problems.
Logins everyone needs to be logged into their own Minecraft account
Versions make sure everyone is running the latest version, this includes the server software if you are using it
Mods if you are using mods, try it without them to make sure they aren't causing problems, easiest way is to move the folder where your mods are stored somewhere else, including the main jar file
Firewalls make sure that your firewall has an exception for the right version of Java, sometimes you can have a few versions installed, which can cause problems. Don't just allow the Minecraft.exe either, since it is just an updater. If your computer is connected to a network that you have told Windows is "public", there are rules in your Windows Firewall that Java set up that will disallow connections from public networks. Try disabling those rules.
Router rules can sometimes disallow connecting to other computers on the same network by default, as a security feature. There's no one way to fix this that works for every router, so you'll have to research your particular router and how to check/change its configuration.
IP addresses try to have a single IP address for each machine, this means don't connect to the wired and wireless at the same time, it can cause problems
Valid IP addresses If you are running Windows, run ipconfig on both machines, and make sure you see 192.168 as the start of the IPv4 address. Also make sure the third digit (usually 0) matches. Google subnet masks if you want to learn how they work. To run ipconfig, you must open the command prompt (cmd) and type in ipconfig, then press enter.
Try Direct Connect various problems can prevent automatic finding from working, try typing the address printed when the world was enabled into the Direct Connect link.
Hopefully this covers all of the most common issues.
Try using direct connect.
This should work; if you get an error or can't follow (I'm doing this off the top of my head), leave a comment.
Further to @Chaosed0 's answer, I had this problem until I noticed that the IP address given by the server wasn't in my private IP range (192.168.*) but was actually on a subnet associated with VMWare's virtual network adapters. As a quick fix I disabled them and the problem went away - I suppose the LAN server is binding to the first interface it comes across and doesn't care which, but I don't know how to select it (or if you can).
So far as answering the question, check that the IP address given on the server is on the same subnet as the client you're trying to connect from, though I don't know what to do if it's not...
There are a couple of things I would check.
Are they both plugged into the same router? This is the one I would check right away. Ensure that you are somehow not on two different LANs, for example one computer being connected to a modem, and then the other computer is connected to a router or VOIP adapter. If they are both using wireless ensure they are both using the same network. That one computer is not connected to a guest network, and the other the normal network.
What network profile are you using? Is it set for home or office, you want it on office to ensure that your computer is discoverable to other computers. To change this if needed
Open Network and Sharing Center by clicking the Start button Picture of the Start button, and then clicking Control Panel. In the search box, type network, and then click Network and Sharing Center.
Next to Connections, click the link for the network connection you want to modify, and then click Properties. Administrator permission required If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
Disable any firewall that you have running
Go on the world, make it LAN, then thare will be a server address at the bottom. Tell your cousin to make a server, then put that address in the server address.
This question already has an answer here:
The problem is that either the server cannot connect to Minecraft.net or that the person getting that error doesn't have a legitimate Minecraft account and so the server is refusing access.
The way to solve this is either to get all players a premium Minecraft account, or to change online-mode to false to stop it from checking the validity of the other account.
You see, with online-mode set to true, the server tries to authenticate every player with the official Minecraft servers as they try to join.
You sound as if you're trying to play with no connection outside of your LAN, thus the server is failing because it can't find session.minecraft.net to authenticate the players.
By setting online-mode to false, you're telling to server to quit bothering trying to authenticate you and your friends with the mothership because you know it won't be able to find it, because you have no internet connection.
Nevermind, I changed the server properties "Online Mode" to FALSE and it worked.
Refresh your DNS cache.