а дали въобще има нещо,което слуша на порта (за VNC май по подразбиране беше на 5900) на сървъра към който се опитваш да се закачиш?
netstat -ant
какво връща?
root@server:~# netstat -ant
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:995 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:8010 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:139 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:5901 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:5005 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:110 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:5006 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:143 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:10000 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:6000 0.0.0.0:* LISTEN
tcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:6006 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:3000 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:5432 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:6012 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:445 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:993 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:6012 127.0.0.1:58704 ESTABLISHED
tcp 0 0 127.0.0.1:58703 127.0.0.1:6012 ESTABLISHED
tcp 0 0 127.0.0.1:5006 127.0.0.1:59209 ESTABLISHED
tcp 0 0 127.0.0.1:41849 127.0.0.1:5005 ESTABLISHED
tcp 0 0 94.155.51.71:53094 94.155.51.71:22 TIME_WAIT
tcp 0 0 127.0.0.1:41845 127.0.0.1:5005 ESTABLISHED
tcp 0 0 127.0.0.1:6012 127.0.0.1:58703 ESTABLISHED
tcp 0 0 127.0.0.1:58704 127.0.0.1:6012 ESTABLISHED
tcp 0 0 127.0.0.1:5005 127.0.0.1:41849 ESTABLISHED
tcp 0 0 127.0.0.1:5005 127.0.0.1:41845 ESTABLISHED
tcp 0 0 94.155.51.71:22 192.168.2.4:15629 ESTABLISHED
tcp 0 0 127.0.0.1:59209 127.0.0.1:5006 ESTABLISHED
tcp6 0 0 :::6000 :::* LISTEN
tcp6 0 0 :::21 :::* LISTEN
tcp6 0 0 :::22 :::* LISTEN
tcp6 0 0 ::1:631 :::* LISTEN
tcp6 0 0 ::1:5432 :::* LISTEN
tcp6 0 0 ::1:6012 :::* LISTEN