Getting Cut & Paste to work in VNC

Sometimes the ability to use cut and paste stops working between your VNC session and the your computer. To get cut and paste to work again just run the following command on the terminal. 

root@earth> vncconfig &

The vncconfig command lunches the vncconfig utility which controls the clipboard function needed for cut & paste to work. Just make sure all the check boxes are checked when the vncconfig utility comes up and cut & paste should start working again.

How to setup SSH Keys

Note - I have a newer version of this how-to. Please click here 

This is a guide on setting up SSH Keys for a UNIX based account. What are SSH keys you ask? They are means of identifying yourself to an SSH server using public-key cryptography and challenge-response authentication. SSH Keys are considered more secure than using passwords to access systems, because user accounts are authenticated by the server without ever having to send your password over the network. If the passwords are not transmitted then they can't be intercepted.
This guide is not for installing or setting up a SSH server. You must have SSH running on your servers in order to get your SSH keys to work. All the examples are take from a Solaris 10 (SPARC) server. This guide should as work on any UNIX based operating system like Linux, BSD and the Mac.

Create you key pair
The ssh-keygen command will generate a public and private keypair. The keys will be stored at ~/.ssh.The basic command looks like this: ssh-keygen -t [dsa|rsa]  The -t sets the type of keys used. In the example below I create a rsa key pair.

man@earth> ssh-keygen -t rsa
Enter file in which to save the key (/home/man/.ssh/id_rsa): Press [Enter] key
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/man/.ssh/id_rsa.
Your public key has been saved in /home/man/.ssh/id_rsa.pub.
The key fingerprint is:dfhjodfnk
04:be:15:ca:1d:0a:1e:e2:a7:e5:de:98:4f:b1:a6:01

Make sure you don't use a blank passphrase. Doing this is very insecure. Having a blank passphrase defeats the purpose of having having the extra security of a key exchange setup. It is also import to never give out your private key, which also compromises security of your account.

Copy public key
Copy you public key to the authorized_keys file on the remote server.

man@earth> scp ~/.ssh/id_rsa.pub moon:~/.ssh/authorized_keys

If your home directory automounts across a lot of servers. You can copy it over with the cat command.

man@earth> cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

Setup Agent
At this point, when you login you get prompted for a passphase. To stop this from happening you need to setup a SSH agent. Run the command below and type in your passphare when prompted.

man@earth> eval `ssh-agent`
man@earth> ssh-add
Enter passphrase for /home/man/.ssh/id_rsa:
Identity added: /home/vivek/.ssh/id_dsa (/home/man/.ssh/id_rsa)

There are other ways to set up the agent such as using the gnome GUI for example. Unfortunately that only works if your running a gnome desktop. If your a VNC user, you should start your VNC server session after starting your agent in the same terminal. This way all your terminals launched in your VNC session, will use the same agent.

One issue with agents is that sometimes you end up running a lot of agents. Run the command below and kill any agents that you are not using, as a good practice.

man@earth> ps -ef | grep agent

References
g-loaded.eu
Symantec: SSH and ssh-agent

If you have any questions or comments please post below.

How to use VNC to view a remote system

VNC is a free 3rd party program that allows a remote login, similar to Remote Desktop in Windows or Daemonware. One nice thing about VNC, is that it's multi-platform. It works on Windows, UNIX, BSD, Linux and MAC. The down side to using VNC is that it's insecure, but you can wrap it in a SSH tunnel. Most of my experience with VNC is on Solaris and Red Hat. Most of the examples below are from a Solaris server.


To see if any VNC sessions is running on your server run the command below. # ps -ef|grep vnc
If you have a session running it will look like this. rich 15137 14170  0 Nov 24 ?    0:00  vncconfig -iconic
rich  538  8833   0 Nov 24 ?    7:34  Xvnc :1 -desktop server:1 (rich) -auth /home/rich/.Xauthority -geometry 1900
To start a basic VNC server session just type vncserver. # vncserver After you run this command you will get a session ID number. For example the first user of VNC server will get session number 1. When you connect to the session from a remote computer you use the hostname:1.

You will also need to set the VNC password to connect the session. # vncpasswd This sets the password for your account.

If you want more options, check the these popular options below. For screen size use -geometry widthxhight. If the computer you are connecting from doesn't have VNC Viewer installed then, you can use the -httpd option to connect using a web browser.  # vncserver :3 -geometry 800x600 -http

VNC is installed on MACs and you can turn on the VNC server by going to System Preferences -->  Sharing. Select Remote Management and then click Computer settings. In the drop down select VNC viewers may control screen with password. Then put in desired password in box.

The xstartup file controls the desktop you get. Uncomment lines 4 & 5 to get a gnome desktop.

Sometimes you need to shutdown the VNC session your using. # vncserver -kill :#Replace # with the session number VNC gave you.

Now that you have started the VNC server you will want to connect to use it. From a UNIX or Linux  you run the following command. vncviewer hostname:1 # vncviewer server1:1
If you are using VNC from a Windows PC, then there is a VNC viewer application.


Warning: If you auto-mount your home directory. Beware that different operating systems have different setting in the xstartup file. All VNC sessions use the same xstartup file, so changes made by you or the VNC program will effect the VNC experience. I ran into an issue when I tried to use the gnome desktop on both a RHEL & Solaris 10 servers. When I got the gnome desktop working for RHEL the gnome desktop was unusable with Solaris 10. The best way to get around this is to use different accounts or different windowing programs on different operating systems.

Important VNC files
$HOME/.vnc/xstartup -- The file that controls them all. This is the main config file used for the session on VNC server.

$HOME/.vnc/passwd -- The VNC password file

$HOME/.vnc/host:display#.log -- The log file for Xvnc and applications started in xstartup

$HOME/.vnc/host:display#.pid -- Identifies the Xvnc process ID, used by the -kill option.

Package list for Solaris 10
SUNWxvnc                VNC Server
SUNWvncviewer       VNC Viewer