How to connect remotely to the GBO network#

This connection is needed for performing observations and is also available to process data.

There are multiple ways to connect remotely to the GBO network:

FastX connection
VNC connection

FastX connection#

We recommend the FastX connection using your browser. FastX is a commercial product that provides remote access to Linux systems by giving you a full graphical interface within your browser. No software is required on your machine except a browser. This service is available from anywhere that has a reasonable internet connection.

Caution

You should avoid accessing this service from public machines such as at hotels or conferences as these machines are highly likely to be compromised and will record your login credentials.

Accessing the GBO network#

Point your browser at https://ssh.gb.nrao.edu:3443/. You will be prompted for a username and password. This should be your NRAO/GBO username and your UNIX password.

Once you have logged in, you will be greeted by a screen informing you to abide by the terms of the NRAO Computing Security and Computing Use Policies. Click “Proceed”.

../../_images/fastX_gb_login-success.png

Next you will see the FastX dashboard.

In the top right corner you can access your User Preferences, learn about FastX and Sign Out.

For your convenience shortcut connections to our different computing machines are provided in the left-hand panel. If you’re actually observing, pick ariel or titania. If you want to process your data, please choose euclid, fourier, maxwell, newton, planck, or thales.

After selecting your target machine, and if your system supports it, you might see a page that allows you the choice between running the FastX session in the browser or via an app on your computer. For the latter to work, you are required to download and install the app.

../../_images/fastX_gb_connection-choice.png

You will be asked for your UNIX password one more time and then you should see your XFCE desktop on the machine of your choice. FastX session should resize your Linux screen automatically to adjust to the size of your browser.

FastX session controls#

While in a FastX session, there is a small drop-down menu in the top part of the window that appears when you hover over it and allows some control over the session.

../../_images/fastX_gb_session-controls.png

From left to right:

House brings you back to the FastX dashboard.
Keyboard allows you to set the keyboard.
People controls the sharing of the session (more here).
Settings allows you to change other settings such as the window size. Tinkering with these settings should not generally be required but on a very slow connection lowering refresh rates and picture quality may be helpful.

Ending a FastX session#

When you are finished, click the home button in the control menu (see above) and close the browser tab that contains the session you were working in. In the FastX starting page you will see a session in the center (Disconnected Sessions). This will expire automatically after 7 days, but if you don’t need it anymore, please terminate the session to help save ressources for your fellow observers.

You can reconnect to a disconnected session by clicking the “play” button.

../../_images/fastX_gb_disconnectedSession.png

Note

Be aware that if a host is rebooted the session will also disappear. Please also bear in mind that due to licensing only a limited number of concurrent sessions are possible.

Is this secure?#

Short answer: Yes! Access to this service is only available over the HTTPS protocol and as such all traffic between your browser and the server is encrypted.

What can’t I do?#

You cannot fire up a browser in a session and access the FastX service in that browser. This kind of recursion is not permitted. As usual the NRAO Computer Use Policy applies to all use of this service.

What to do if the GBO network is down/slow#

Occassionally we experience network issues where either the entire Green Bank network is down or intermittent which causes FastX and VNC sessions through Green Bank to be extremely slow.

Suggested checks:

If you are unsure which end of the internet is slow, try running a speed test on your network connection. If your speed levels are where they should according to your internet provider, the problem is likely on the Green Bank end of the network.
Check this status page to see the status of the ssh gateways. Orange means that it was down for a small portion of that time slice. Red is down for a significant portion of the time span that slice of the bar covers. Each vertical bar is a day.

In the case that the internet issue is on the GBO side, you can run your FastX or VNC connection through Charlottesville. Or with FastX, if you get kicked out, just keep trying to re-connect.

FastX through Charlottesville#

Point your browser to https://fastx.cv.nrao.edu. You will be prompted for a username and password. This should be your NRAO/GBO username and your UNIX password (the same you’re using to connect to the GBO network described above).

Once you have logged in, you will be greeted by the same screen informing you to abide by the terms of the NRAO Computing Security and Computing Use Policies again. Click “Proceed” to continue to your FastX dashboard.

In the application panel on the left-hand side, you might not see a lot of preset connections yet. You can create your own connection by clicking the circled plus sign next to “Applications”. A pop-up will open. Provide the following details:

Command *: ssh <machine-name>.gb.nrao.edu startxfce4
Run As User: <your user name>
Name: <name of the machine or whatever identifier you want to use>

Available machine names are:

for observing only: ariel, titania
for data processing: euclid, fourier, maxwell, newton, planck, thales

../../_images/fastX_cv_new-application.png

You can permanently save the connection details, by clicking the down-arrow next to Launch and selecting “Create Application”. Then click Launch to start the connection.

../../_images/fastX_cv_new-application_create.png

You will be asked for your password twice: (1) to establish the ssh connection to a machine called polaris and then (2) to log into the machine you choose (ariel in the example here). You may experience longer load times to start the session, but once you’re logged in, things usually work well.

If you don’t see your newly created application in the dashboard, you might need to change the filter settings by clicking the filter icon and selecting “User”.

VNC through Charlottesville#

If you cannot even connect to green bank to start your VNC session through Charlottesville instead:

ssh username@ssh.cv.nrao.edu
ssh titania
vncserver -geometry [horiz_len]x[vert_len] :n

Hint

Manually choose a higher number session to decrease the likelihood that that number is being used on either a GBO or Charlottesville computer.

Then make your tunnel

ssh -N -C -L 590n:titania.gbt.nrao.edu:590n [username]@ssh.cv.nrao.edu

And with your VNC viewer connect to localhost:590n

Hint

You may encounter an error when trying to create a tunnel through Charlottesville bind [\:\:\#]:590\#: address already in use, channel_setup_fwd_listener_tcpip: cannot listen to port: 590\#, could not request local forwarding This was thought to mean that that # port was already taken on a Charlottesville computer so you will have to choose a different VNC session number. Hence the earlier suggestion to manually choose a session number that is higher initially to avoid such issues.

Acknowledgement

We would like to thank Joeri van Leeuwen (UBC), Tom Troland (U. Kentucky), and Jeff Mangum (NRAO CV) who kindly provided the basis of these VNC instructions. We appreciate the time they took to make VNC easier for all remote observers.

How to connect remotely to the GBO network

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How to connect remotely to the GBO network#