[JAVA] Libreria ftp4j

[PhysX]

Ho scritto questo semplice codice di prova che deve solo elencare i file su un server FTP:

Codice PHP:

import it.sauronsoftware.ftp4j.*;

public class FTPtest {

    public static void main(String[] args) throws Exception {

        FTPClient client = new FTPClient();
        client.connect("ftp.it.debian.org");
        client.login("anonymous", "");

        client.changeDirectory("/debian/pool/main");
        String dir = client.currentDirectory();
        System.out.println("Directory corrente: " + dir);
        
        FTPFile[] list = client.list();
        for (FTPFile l: list) {
            System.out.println(l.getName());            
        }

        client.disconnect(true);
    }
} 


Il problema è che con qualunque server FTP lo provo mi da sempre l'errore Exception in thread "main" java.net.SocketException: Connection reset:

Exception in thread "main" java.net.SocketException: Connection reset
	at java.net.SocketInputStream.read(Unknown Source)
	at java.net.SocketInputStream.read(Unknown Source)
	at sun.nio.cs.StreamDecoder.readBytes(Unknown Source)
	at sun.nio.cs.StreamDecoder.implRead(Unknown Source)
	at sun.nio.cs.StreamDecoder.read(Unknown Source)
	at sun.nio.cs.StreamDecoder.read0(Unknown Source)
	at sun.nio.cs.StreamDecoder.read(Unknown Source)
	at java.io.InputStreamReader.read(Unknown Source)
	at it.sauronsoftware.ftp4j.NVTASCIIReader.readLine(NVTASCIIReader.java:105)
	at it.sauronsoftware.ftp4j.FTPCommunicationChannel.read(FTPCommunicationChannel.java:142)
	at it.sauronsoftware.ftp4j.FTPCommunicationChannel.readFTPReply(FTPCommunicationChannel.java:187)
	at it.sauronsoftware.ftp4j.FTPClient.openPassiveDataTransferChannel(FTPClient.java:3614)
	at it.sauronsoftware.ftp4j.FTPClient.openDataTransferChannel(FTPClient.java:3549)
	at it.sauronsoftware.ftp4j.FTPClient.list(FTPClient.java:2078)
	at it.sauronsoftware.ftp4j.FTPClient.list(FTPClient.java:2273)
	at FTPtest.main(FTPtest.java:20)

Ho guardato i sorgenti di ftp4j e fino a quel punto mi sembra tutto liscio, mi sa che è un problema a basso livello del protocollo FTP, magari c'è qualche parametro da settare... avete qualche idea?