Offline Mode/Cracked servers - What are they?

A cracked, or offline-mode server is a server run with offline mode triggered to false in the server.properties file. It's seen in the properties file as this: "online-mode=false".

You've probably heard of it, but a lot of people don't know exactly what it does. You can still log onto these servers
just fine too. What is difference exactly?

Normally, by default, the properties file has it set to true. What setting it to false does: Is it turns off user-name authentication through Mojang. Normally, when you log into a public server, you don't directly connect to it first, instead it runs your account through Mojang's authentication servers. This determines if you're using a paid Minecraft account, and if you are, it lets you proceed, and you connect to the Minecraft server.

Running a server in offline-mode turns this username authentication off. This way, you don't need a paid account to play, instead, you can use the Offline mode in Minecraft. This is accessible when you're using the launcher, if you don't enter an account, or if you can't connect to the Mojang servers, it says "Login Failed", or some other error, and gives you the option to play in offline mode. From here, you can choose to play Single player. Normally you can't play Multiplayer, but if you have some offline-mode server IPs handy, you can connect to them and play multiplayer!

However, if you simply use Minecraft's Offline mode, to log into a server also in offline mode, it will simply use the Username "Player". This will also prevent other people using the Minecraft Offline mode from connecting, because they'll just have the "Player" ID as well. Some Bukkit servers fix this, however. But maybe you want to use your name. You can still log into any offline-mode server with your paid account, and it works just fine. There is however, another solution: There's "cracked" clients/launchers specifically designed to log onto offline servers. They can provide a username, that the offline mode server will use to ID you, instead of the "Player" that the normal Minecraft sends.

There's another huge advantage to this setting- the ability of users being able to login to your server isn't affected at all by the status of Mojang's services. For example: if Minecraft.net is down(and it is a lot) people can't login to normal, online-mode=true public servers until it's up again. However, when online-mode is set to false, logging in doesn't run you through Minecraft.net at all, you just connect straight to the server. And it means that while other public servers are down, offline mode servers still work like a charm.

Regardless, there are several disadvantages to playing on an offline server, even with a launcher that can give you a name. The biggest one is that people can log in as you, or whatever name you used. You can even log on with a name of a paid account. You can't have Admin rank on these servers either, because if there was, people could simply logon as the name of an Admin to get Admin rank.

But! There's a Bukkit plugin that protects people's gameplay sessions under a certain name, and what it does is that it spawns you, usually in a jail or enclosed area, and you can't build or play until you create a password under the Username you're using, or entered the password for the username you're using. It doesn't use the passwords from Minecraft paid accounts, it's the server's own authentication system separate from Mojang's.

However-The authentication is very primitive, and if people get banned under one name, they can just log in under another and keep trolling. To tell the truth: Offline-mode servers do give you Minecraft gameplay, but it's not called online mode for a reason-it's not meant to be run publicly as a server. It was mostly made for LAN Minecraft gameplay, or server testing.

If you want the full experience of Minecraft, BUY a Minecraft.net account. You get to have your own custom skin too. And you're supporting Mojang. Don't put off spending $30, instead, get the full experience. To me, you're just compromising a bit too much if you're relying on Offline-mode servers just to play Online Minecraft Multiplayer.