In the lab, we use the college's UNIX servers, remus.amherst.edu and romulus.amherst.edu (heretofore, simply remus and romulus). Note that you can login to these machines using the VNC Viewer program on any of the college's public Windows machines (e.g., in the Computer Center). However, you may want to use your own computer, and you may even need to connect from off-campus. This section provides instructions for using remus/romulus from (nearly) everywhere.
When not working in the lab, your method of connecting to remus/romulus will be a bit different from in the lab. Specifically, you can connect textually (just a shell -- no windows, no graphics) using a program named ssh. If you have a sufficiently fast network connection, you can use both ssh and VNC together to obtain a full graphical connection to the servers. This section will desribe how to use both pieces of software to establish both textual and graphical logins.
In order to connect textually, you will connect using ssh alone. To connect graphically, you must first establish an ssh connection before using VNC to get the same graphical window that you use in the lab. Here, we begin with the ssh connection necessary for any login. Follow these steps to connect to remus/romulus with ssh, establishing an encrypted tunnel for VNC connections:
Connect to romulus or remus using an SSH client configured to establish the tunnel: The choice of SSH client and the description of how to use it depends on the type of system that you are using. Below are instructions for Mac OS X, Linux/UNIX, and Windows systems.
ssh -L 5900:localhost:5900 username@romulus.amherst.edu
Of course, you would replace username with your college username. You will be prompted for your password, so simply provide it. Assuming that your login proceeds normally, you will have established a tunnel for VNC conncetions (if you want to use one). Moreover, you will connected to a shell, ready to receive commands. Here, you can run Emacs, and compile and run Java programs.
Windows: First, get PuTTY from Winsoft. (Here is the PuTTY home page if you want to learn more about it). It is a good, free, Windows ssh program.
Once you have downloaded PuTTY, follow the steps below to login via ssh, creating a tunnel through which VNC can connect. Note that you only have to do these once -- at the end of these steps, we'll save the settings so that you can simply recall them later.
Double-click on the PuTTY icon to run the PuTTY program. You should see window come up that is titled PuTTY Configuration.
On the left-hand side of this window is a section labeled Category. Within that section, under Connection, there is an item named SSH that has a plus-sign next to it. Click on the plus-sign to drop down another submenu under SSH.
Click on the Tunnels item in that submenu. The right-hand side of the window should now be titled, Options controlling SSH port forwarding.
On the right-hand side of the window, mid-way down, under, Add new forwarded port:, enter 5900 for the Source port and remus.amherst.edu:5900 for the Destination. Then click the Add button. You should see, in the mini-window above, an entry that reads, L5900 remus.amherst.edu:5900. (Note that under Destination, you could also have entered romulus.amherst.edu:5900 -- it doesn't matter which.)
On the left-hand side of the window, under Category:, move to the top of that listing and click on Session. The right-hand side should now be titled, Basic options for your PuTTY session. Under Host Name (or IP address), enter remus.amherst.edu (or romulus.amherst.edu, if that is the machine you specified when making the tunnel).
In that same window, under Load, save or delete a stored session, enter remus tunnel (or romulus tunnel, as appropriate) under Saved Sessions. Then, click the Save button. The entry remus tunnel should appear just below the Default Setting entry.
Finally, double-click the remus tunnel listing. That will open a new terminal window. PuTTY will present the prompt, login as:, and here you should enter your college username. It will then prompt for your password, at which point you should enter your college password. You will finally be presented with a shell prompt just like the one you see in lab within the terminal window. Congratulations, you're connect!
Open a VNC connection: Now that you have established an ssh login and tunnel, you can use VNC to establish a full graphical login. Again, the software used in system dependant, and I describe how to use software for each of the systems described above:
Mac OS X: Download a copy of Chicken of The VNC (yes, that's really its name) from its home page. When you've downloaded this file, double-click it to mount the disk image that it contains -- you will see a new disk on your desktop named Chicken of the VNC. Double-click that disk, and you will see a large icon for the program. To install it, simply drag it into your Applications folder, and then launch it like any other application.
When you start CoTVNC, fill out the window that appears like so:
Click Connect, and a new window should appear containing an entire graphical interface to whichever server you have established an ssh connection. Note that, if your VNC window is larger than your screen, then under the Window menu, you can select Fullscreen Mode to have VNC take over you entire screen.
Linux/UNIX: Again, recent distributions have a VNC client included, or they make it easy to install. If you are using Debian, Ubuntu, or some derivative of those, you should be able to use the following command, as the superuser, to install what you need:
apt-get install xtightvncviewer
Similarly, if you use a Redhat distribution, such as Fedora, you can install VNC as the superuser like this:
yum install vnc
For other Linux or UNIX distributions (e.g., SUSE, FreeBSD, NetBSD, OpenBSD, Solaris), I will simply trust that you know enough about your system to find and install a VNC client. Alternatively, you download the RealVNC client as source code from the RealVNC home page.
Once you have the VNC client software installed, you must be logged into your machine and running an X-Windows server on your console. Open a shell, and give the following command:
vncviewer localhost
A new window should appear containing an entire graphical interface to romulus or remus (whichever you connected to via ssh). To obtain full screen mode, trying pressing the F8 key, and a drop-down menu should appear with that option.
Windows: You can download a copy of the RealVNC Viewer. To do so, follow these steps:
Go to the RealVNC download page.
On this page, select the Free Edition.
You will then be led to a page where they ask for a little information about you; feel free to provide it or not, and then click the Proceed to download button.
The next window lists a number of versions of VNC for different kinds of computers and operating systems. Find VNC Free Edition for Windows (which is likely at the top) and click its Download button next to the Executable option (not the Zip Archive option).
The next page will show you the license for downloading and using the software. Read it, and if you agree, click the I accept these terms and conditions checkbox, and finally click the Download button. That will download the installer to your computer.
Find the downloaded file (probably on your Desktop), and double click the VNC icon. This program will install the VNC software on your computer.
Once installed, you can go to the Start menu, look under All Programs, and then find the RealVNC viewer program. When you start it, fill out the window that appears like so:
A new window should appear with an entire graphical interface to the UNIX server, just as you see in the lab. To obtain full screen mode, click on the upper-left corner of the window frame to get the window's drop down menu, and select the full screen option.
Login to remus or romulus: Now that you are graphically connected, simply use the login window. Everything from here should proceed as it does in the lab.