一、简介

VNC是Virtual Network Computing的字母缩写，是一种桌面共享系统或者说协议。可以用来控制和访问远程桌面。一般具有相似功能的程序包有TigerVNC, TightVNC, Vino(Gnome桌面默认使用)，x11vnc， krfb(KDE桌面默认使用), vnc4server等。下面示例用来演示如何在ubuntu18.04 TLS系统上安装配置TigerVNC来访问Gnome3桌面。

二、安装配置

相关程序包参考地址：https://www.realvnc.com/en/connect/download/viewer/linux/

安装配置参考：

https://www.cyberciti.biz/faq/install-and-configure-tigervnc-server-on-ubuntu-18-04/

https://computingforgeeks.com/how-to-install-vnc-server-on-ubuntu/

1.安装桌面环境程序包

假如ubuntu系统没有桌面程序，需要先行安装

# apt install ubuntu-gnome-desktop
# systemctl enable gdm
# systemctl start gdm

2.安装tigerVNC及依赖程序包

$ apt install tigervnc-standalone-server tigervnc-xorg-extension tigervnc-viewer

3.设置VNC密码

# vncpasswd
Password:
Verify:
Would you like to enter a view-only password (y/n)? y
Password:
Verify:

4.配置VNC文件

在用户所在家目录下创建~/.vnc/xstartup，并写入如下内容：

vi ~/.vnc/xstartup

#!/bin/sh
# Start Gnome 3 Desktop 
[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
vncconfig -iconic &
dbus-launch --exit-with-session gnome-session &

5.启动VNC

# vncserver -localhost no

VNC命令使用参考：

# vncserver --help
usage:
  vncserver -help|-h|-?            This help message. Further help in tigervncserver(1).

  vncserver [:<number>]            X11 display for VNC server
            [-dry-run]             Take no real action
            [-verbose]             Be more verbose
            [-useold]              Only start VNC server if not already running
            [-name <desktop-name>] VNC desktop name
            [-depth <depth>]       Desktop bit depth (8|16|24|32)
            [-pixelformat          X11 server pixel format
              rgb888|rgb565|rgb332   blue color channel encoded in lower bits
             |bgr888|bgr565|bgr233]  red color channel encoded in lower bits
            [-geometry <dim>]      Desktop geometry in <width>x<height>
            [-xdisplaydefaults]    Get geometry and pixelformat from running X
            [-wmDecoration <dim>]  Shrink geometry from xdisplaydefaults by dim
            [-localhost yes|no]    Only accept VNC connections from localhost
            [-httpPort     port]   Port of internal http server
            [-baseHttpPort port]   Calculate http port from base port + display nr
            [-fg]                  No daemonization and
                                   kill the VNC server after its X session has terminated
            [-autokill]            Kill the VNC server after its X session has terminated
            [-noxstartup]          Do not run the Xvnc-session script after launching Xtigervnc
            [-xstartup]            Specify the script to start after launching Xtigervnc
            [-fp fontpath]         Colon separated list of font locations
            [-cleanstale]          Do not choke on a stale lockfile
            [-SecurityTypes]       Comma list of security types to offer (None, VncAuth,
                                   Plain, TLSNone, TLSVnc, TLSPlain, X509None, X509Vnc,
                                   X509Plain). On default, offer only VncAuth.
            [-PlainUsers]          In case of security types Plain, TLSPlain, and X509Plain,
                                   this options specifies the list of authorized users.
            [-PAMService]          In case of security types Plain, TLSPlain, and X509Plain,
                                   this options specifies the service name for PAM password
                                   validation (default vnc if present otherwise tigervnc).
            [-PasswordFile]        Password file for security types VncAuth, TLSVnc, and X509Vnc.
                                   The default password file is ~/.vnc/passwd
            [-passwd]              Alias for PasswordFile
            [-rfbauth]             Alias for PasswordFile
            [-X509Key]             Path to the key of the X509 certificate in PEM format. This
                                   is used by the security types X509None, X509Vnc, and X509Plain.
            [-X509Cert]            Path to the X509 certificate in PEM format. This is used by
                                   the security types X509None, X509Vnc, and X509Plain.
            <X11-options ...>      Further options for Xtigervnc(1)
            [-- sessiontype]       Arguments for the VNC startup script Xvnc-session

  vncserver -kill                  Kill a VNC server
            [:<number>|:*]         VNC server to kill, * for all
            [-dry-run]             Take no real action
            [-verbose]             Be more verbose
            [-clean]               Also clean log files of VNC session

  vncserver -list                  List VNC server sessions
            [:<number>|:*]         VNC server to list, * for all
            [-cleanstale]          Do not list stale VNC server sessions

此时查看主机所监听端口显示如下：

# netstat -tanlp | grep vnc
tcp 0 0 0.0.0.0:5901 0.0.0.0:* LISTEN 57275/Xtigervnc 
tcp6 0 0 :::5901 :::* LISTEN 57275/Xtigervnc

常用命令：

结束运行中的vnc：

vncserver -list （查看所有运行的vnc进程）

vncserver -kill :1 （结束编号为1的vnc进程）

vncserver -kill :* （结束所有vnc进程）

6.安全性介绍

VNC是一种明文的、不安全的网络协议。要使通信安全，必须使用VNC服务器和客户机之间的SSH隧道加密服务器-客户机连接。在Linux或Unix桌面中，输入以下ssh命令设置ssh隧道:

# ssh user@remote-server -L 5901:127.0.0.1:5901

这样就可以通过ssh命令通过vnc连接远程主机了，如下所示是我的测试结果。