方法：
#安装xrdp
sudo apt-get install xrdp
#安装vnc4server
sudo apt-get install vnc4server tightvncserver
#安装xubuntu-desktop
sudo apt-get install xubuntu-desktop
#向xsession中写入xfce4-session
echo "xfce4-session" >~/.xsession
#开启xrdp服务
sudo service xrdp restart
问题：
connecting to sesman ip 127.0.0.1 port 3350
sesman connect ok
sending login info to sesman
xrdp_mm_process_login_response: login successful for display
started connecting
connecting to 127.0.0.5910
tcp connected
security level is 2 (1 = none, 2 = standard)
password failed
sudo vi /etc/xrdp/sesman.ini
#找到 [Xvnc]
#add the "param"
param8=-SecurityTypes
param9=None
#then run restart
sudo service xrdp restart
reference：
https://blog.csdn.net/RenDuData/article/details/86288332