Connection hangs on session.connect

[loomcode]

Connection just hangs. I'm successfully connecting with the same host, user, and port from terminal and from an implementation I wrote in python using paramiko (I'm using RSA keys, no passwords). Increasing the timeout has no effect and no exceptions are thrown. I was using version 1.55 but have also tried 1.5 to see if it's version related. I'm connecting between two linux ubuntu/mint systems if that helps.

JSch jsch = new JSch();
jsch.setKnownHosts("/home/user/.ssh/known_hosts");
Session session = jsch.getSession(this.username, this.ip, 21);
Hashtable<String, String> config = new Hashtable<String, String>();
config.put("StrictHostKeyChecking", "no");
config.put("PreferredAuthentications", "publickey");
session.setConfig(config);
session.connect(5000);
System.out.println(session.isConnected());