I'm looking to setup a Minecraft LAN server on my college's computers (I do a game development course and am currently on networking so this is relevant). Also, just before I get started, I own a legitimate Minecraft account.

There is one slight problem. I think Java may be blocked in the firewall (which I can't access because I'm a student) because when I try to login to the launcher it throws this error:

ConnectException: Connection refused: Connect

My question is this: Is it possible to launch the game without having to log in? I already have the game files from AppData copied over onto a flash drive (which I'm trying to run it from.

I heard from this question that you could launch it with a command while getting a username and session ID from here: https://login.minecraft.net?user=<username>&password=<password>&version=13 but as that is a request to the login servers, it may or may not work at college. Is there any better way to launch it?

P.S. Counter-Strike and Cube 2 multiplayer worked so I know the LAN server will be okay. It's just launching the game I need help with.

  • Note I've removed the request for a cracked launcher - that's not something we would deal with here.
    – JonK
    Commented Dec 8, 2015 at 18:40
  • @JonK Fair enough. That was for the worst case scenario though.
    – Pyroglyph
    Commented Dec 8, 2015 at 18:41
  • I can understand that - but it's a site policy here; we don't deal in cracked or otherwise pirated games or software. The rest of your question is fine though.
    – JonK
    Commented Dec 8, 2015 at 18:42

3 Answers 3


What I have done that works, but only if you've opened the game once and logged in prior to this and saved the settings/profile, is to make sure no instance of the game not the loader is running. Then disable your internet, load the launcher and it should say 'play offline'. Press and play, once the game is loaded you should be able to safely reenable your internet.

  • I think when you can't connect to the servers in the first place, disconnecting your internet connection entirely is not needed.
    – MrLemon
    Commented Dec 11, 2015 at 9:54
  • Yeah. But the launcher knows when you are connected before logging in. But if either way works the great.
    – ydobonebi
    Commented Dec 11, 2015 at 18:55
  • Just letting anyone in the future know that this does not work with the new launcher.
    – Zelo101
    Commented Jan 11, 2018 at 17:24

One thing you could try is to make a VPN tunnel to your house and have the game authentication happen through your home internet. You'll have a little bit of latency but if you're running local it wont matter. If you want local multiplayer this might not work very well however.

Another idea is use a program like MultiMC (Which is 100% legitimate and follows the TOU of Minecraft) with it as long as you've authenticated yourself once you should be able to start Minecraft with "Play Offline" to play single player or insecure local multiplayer.

  • I had a look at MultiMC before but you still have to login to Minecraft (which may not be possible at college).
    – Pyroglyph
    Commented Dec 10, 2015 at 11:13

At my school (university), there is no possibility to login into any MC server, too. I did not tested on school computers, just at my laptop using Eduroam wi-fi, but the network is same - school one...I assume you will have similar one.

The thing is that I CAN connect (or launch MC at all, now just don't remember, if it gets valid token), BUT I even cannot ping servers in Multiplayer menu.

Same is with web-console for server, it just cannot connect. I experienced same behaviour also with some other games.

Resume: There are probably blocked game ports on the network, because it is for educational thingies only. The solution would be to use some "valid" ports, but hey, that might be quite advanced thing, but probably not impossible. Try to scan your network to get more info about it.

PS: You need to login at least once from that computer to have valid session, but I quite don't know if MC uses same ports to communicate with Mojang servers as with MC servers (probably yes). If yes, there might be way to just force it to use another port (which is open by school network), then it could all work as expected.

  • I'm not looking to join a multiplayer server online. I'm looking to literally just launch the game.
    – Pyroglyph
    Commented Dec 10, 2015 at 11:12
  • The fact that you can do things on your school network that OP has stated he cannot do on his shows that the assumption that all school networks are similar is just wrong.
    – MrLemon
    Commented Dec 10, 2015 at 12:45

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