Solved Get the IP they connect through?

Hey, so I am changing my server's IP to a domain and I was wondering if I could code a plugin were when the connect through the old IP it kicks them. I know kicking and all that it's just I don't know how to find the IP they connect though. Thanks in advance

 

Hello, this is my first time answering a question on a forum so I hope it goes well. I think this idea is interesting and I think I could understand what you meant (it was worded a bit oddly).
So, to find the ip address that a player connected from is relatively simple, but finding the ip address they connected to (as to distantiatefrom different host name) is slightly more difficult. But Bukkit has a way to handle this. Utilizing the event PlayerLoginEvnet (look it up in the javadocs here https://hub.spigotmc.org/javadocs/bukkit/) you can find the ip address a player tried to connect to. I have written a simple plugin to track these event and print out the data. Here is the source:

Code:

public class Test extends JavaPlugin implements Listener
{
    @Override
    public void onEnable()
    {
        //setup the listener, this is straightforward and for simplicity sake, the main class is the listener.
        getServer().getPluginManager().registerEvents(this, this);
    }

    @Override
    public void onDisable()
    {
        //Remove the listener, this is good for the saving memory
        PlayerJoinEvent.getHandlerList().unregister((Listener) this);
    }

    @EventHandler
    public void onLogin(PlayerLoginEvent e)
    {   
        //report the event to the server log
        String msg = e.getPlayer().getName() + " has joined to " + e.getHostname();
        Bukkit.getLogger().log(Level.INFO, msg);
    }
}

This is how the output appeared (at least the relevant information with my ip and host name censored):

This was a connection with my public ip inputted into the server address. It shows that I tried to connect to a list of numbers that is my ip then a port. (censored ip)
[21:29:58] [Server thread/INFO]: flyguy23ndm has joined to xxx.xx.xxx.xxx:2002

This was a connection using my purchased domain name as the inputted server address. It shows that I treid to connect to a text address as opposed to a list of numbers. (censored domain name)
[21:30:10] [Server thread/INFO]: flyguy23ndm has joined to xxxxx.com:2002
​

I'm sure that through some string parsing and a blacklist of non-wanted domain names you could setup what you want. The code could even be something as simple as this:

Code:

if(blacklistedDomains.contains(e.getHostname()))
    e.disallow(PlayerLoginEvent.Result.KICK_OTHER, "Don't use this host name anymore, use (insert host name here)");

Hope this solves your problem .

 

@flyguy23ndm Thanks, that was very helpful (Nice first job!)