FAQs

Emergencies

How do I contact you in an emergency?

If email is not working or responsive, please call:

Bill Maloney at 617-438-2963
Mike Hobbs at 617-438-5960

What do I do if I think my machine has a virus?

Accounts and Passwords

I want to change my password. How do I do that?

Each MTL user has two main passwords to access computers. To login to computers in the MTL Windows domain (MTLWIN), there is a MTL Windows domain password. To login to UNIX computers, access MTL e-mail or login into MTL Coral, there is the MTL MUMMS password. These passwords are stored and managed separately and thus must be updated using separate methods.

Important Note: The old MTL Web Member account has been retired and is no longer used. If you are a MIG member and are looking for information on how to gain access to exclusive MIG web content then please visit here

To change your MTL Windows domain password

  • Log in to any PC in the MTLWIN domain
  • Press CTRL-ALT-Delete
  • Click on the “Change Password” button

To change your MUMMS password

  • Go to MTL MUMMS
  • Login with your current MTL user name and password.
  • Click on the Modify Your Password link on the main page.

I forgot my password. How do I reset it?

If you have forgotten your MTL MUMMS password, then you can click on Lost or Forgot Your Password on the MTL MUMMS Login page and follow the instructions. If this does not work for you then you will need to have your password reset in person by one of the MTL IT staff. Note that passwords are never sent through e-mail.

If you have forgotten your MTL Windows domain password, then you will need to visit the MTL IT Staff in 39-317 and have the password reset in person.

If you have problems changing any of your passwords, please stop by 39-317.

I am confused. What passwords go with what account?

Please see the description above under I want to change my password. How do I do that?

Network Storage

What is the Z: drive?

When you log in to the Windows MTLWIN domain, your UNIX home directory is mounted as the Z: drive. What is your UNIX home directory? When you sign up for an MTL account, a directory is created for you on an MTL UNIX server. Where your UNIX home directory actually resides does not matter because Z: drive access is transparent.

How do I mount the Z: drive manually?

  • Open Windows Explorer (Window Key + E)
  • At the top, click "Map Network Drive"
  • Select your drive letter.  Normally it is Z but it really does not matter.
  • In the Folder box put "\\mtl-home\<your_username>" without the quotes.
  • i.e. \\mtl-home\johndoe
  • Click Finish.

How do I use the Z: drive?

Store your important data there. Remember that Z-drive space is located on MTL UNIX servers and is shared with other MTL users so if you fill it up you affect others as well as yourself. Also, make sure not to install applications there. Applications should be installed onto the local client’s hard drive (the C: drive). Finally, do not fill up the space with personal multimedia files.

Remote Connections

I want to connect to the MTL servers to run CAD tools, how do I do that?

It seems that many CAD users are Using VNC to connect remotely to the MTL CAD servers or their own research group servers. The following general HOW TO guide describes how to get VNC set up and to run it securely through an SSH tunnel.

In this example, we will use your_group’s_UNIX_server as the remote server to connect to. This is not the name of an actual server. You should replace it with the name of your group’s UNIX server. If you do not know the name, ask us and we will help you figure it out but it is usually the server where your MTL UNIX home directory (the Z: drive) is stored.

As always, these are meant to be general notes to help people get setup and not exact step-by-step notes that will work for everyone. Depending on the client computer that you are using, the exact steps needed to be done may differ a bit. If you have any questions/problems on how to get VNC and SSH set up for your particular computing environment, please send a message to problems@mtl.mit.edu and we will try to help you.

Prerequisites

  1. You will need a SSH client program installed on your client computer. e.g. SecureCRT which is freely available from MIT for Windows.
  2. You will need a VNC client viewer program installed on your client computer. e.g. https://www.realvnc.com/download/viewer/

NOTE: If your client computer is a UNIX workstation then you can use the built in VNC and SSH clients that should be available.

Creating a VNC Server Session

NOTE: If you have already run a VNC server within MTL before then you can probably skip steps 2-4.

  1. Login/SSH to your_group’s_UNIX_server.mit.edu
  2. Run the following command:

% vncserver

Enter a password for your VNC sessions. Note the session number that is created.

It will look something like:

>your_group’s_UNIX_server:/homes/<your MTL username>% vncserver

New 'your_group’s_UNIX_server:34 (<your MTL username>)' desktop is

your_group’s_UNIX_server:34

Where the session number in this example is 34

  1. Edit/Create your VNC xstartup file found in ~<your MTL username>/.vnc

Something like this should work:

#!/bin/sh
unset DBUS_SESSION_BUS_ADDRESS
unset SESSION_MANAGER
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
RHVER=`cat /etc/redhat-release | awk '{print $7}' | awk -F. '{print $1}'`
if [ $RHVER = '7' ]; then
mate-session &
elif [ $RHVER = '6' ]; then
gnome-session &
fi
exit 0

  1. Run the following command to end the session created above:
% vncserver -kill :<session number from above>

( e.g. vncserver -kill :34 )

  1. Run vncserver again and specify a session number

% vncserver :<N>  -localhost -NeverShared=true -DisconnectClients=false

where <N> = a number for your session e.g. 34

( e.g. vncserver :34 -localhost -NeverShared=true -DisconnectClients=false )

The other arguments listed will increase the security of your session by not allowing anyone to try and connect to it from another computer and by not allowing it to be shared.  In addition, it will not disconnect a currently connected session if another connect request comes in.  So, make sure to always disconnect your session when finished if you tend to connect from multiple clients during the day.

Now that you have a session running, you can connect to it in a secure way from a remote client computer.

Connecting to a VNC Server Session

  • Connecting from a Windows desktop client computer

    Run SecureCRT (these notes are specific to SecureCRT 7)

    Choose Connect from the File menu

    Right click on Sessions and choose New Session

    Choose Protocol: ssh2 and click Next

    Enter the hostname: your_group’s_UNIX_server.mit.edu

    Enter your UNIX username

    Click Next until you reach the page with Finish on it

    Change session name to "your_group’s_UNIX_server-VNC"

    Click Finish

    Right click on the new session and choose Properties

    Choose Port Forwarding from the left hand menu

    Choose Add

    Enter your_group’s_UNIX_server-VNC for the name

    Enter local port: 5900 + <M> (where M is any number typically the same as the session number above but see the note below about running multiple VNC client sessions on the same machine). (e.g. 5934)

    Enter remote port: 5900 + <N> (where N must be number of the vncserver session from above). (e.g. 5934)

    Enter the vncviewer client for Application

    e.g. C:\Program Files\RealVNC\vncviewer\vncviewer.exe

    Enter "localhost:<P>" for the arguments (where P must be the same as M above). ( e.g. localhost:34 )

    Click OK until you close out of all dialog boxes.

    Highlight the new session and choose 'Connect'

  • Connecting from a UNIX desktop client computer

    Open up a terminal window and run the following command:

    % ssh -L <local port>:localhost:<remote port> -N your_group’s_UNIX_server.mit.edu

    where

    <local port> = 5900 + <M> (where M is any number typically the same as the session number above but see the note below about running multiple VNC client sessions on the same machine).

    <remote port> = 5900 + <N> (where N must be the number of the vncserver session from above).

    Open up another terminal window and run the VNC viewer command:

    % vncviewer localhost:<M>

    where

    <M> = the same as <M> in the ssh directions above.

  • Connecting from a Mac desktop client computer

    Open up a terminal window and run the following command:

    % ssh -L <local port>:localhost:<remote port> -l <MTL_username> -N your_group’s_UNIX_server.mit.edu

    where

    <local port> = 5900 + <M> (where M is any number typically the same as the session number above but see the note below about running multiple VNC client sessions on the same machine).

    <remote port> = 5900 + <N> (where N must be the number of the vncserver session from above).

    There is a built-in VNC client on Macs called Screen Sharing.  Run it and connect to the localhost port you opened in the Terminal window above:

    MacHD->System->Library->CoreServices->Applications->Screen Sharing

    Connect to: localhost:<M>

Multiple Sessions

If you have more than one VNC client session running then you will need to choose a different local port for each of them.  In other words, if you had separate sessions on mtlcad and your_group’s_UNIX_server then one would use 5960 and the other 5961.  If do you choose the same local port, they cannot both run at the same time.

How do I transfer files back and forth from my home computer to my MTL UNIX home directory?

There are a number of options to accomplish this such as using MIT Dropbox or SecureCRT/FX (Windows) available for use from MIT’s software page.  Assuming you have installed SecureCRT/FX or other secure file transfer application, you can securely connect to an MTL general use computer such as mtl-home.mit.edu or your research group server and transfer files back and forth.

CAD

I am getting a black/blank screen when running certain CAD tools within a VNC session

This can occur if the CAD tool requires the use of a real video card in order to display properly within the client application. When you run CAD tools within a remote VNC server session, the program emulates all graphics processing solely within software.  This can then lead to problems most commonly a blank or black screen within the client application.  The following outlines a workaround for Windows client users that may help with this problem, but note that there is no guarantee this will work to solve your specific issue.  If you continue to have problems, you should talk to Mike McIlrath about what specifically you are trying to do.

Note that if your group has its own server that it may already have a dedicated video card in it for this very purpose.  If this is the case, then you should substitute that server instead of mtlsim2.mit.edu in the following instructions.

  • From an SSH client such as SecureCRT, login/SSH to mtlsim2.mit.edu
  • On mtlsim2, run the following:

% xauth merge /etc/opt/VirtualGL/vgl_xauth_key

  • Create/Edit your .vnc/xstartup.turbovnc file if it does not already exist.

The following should work:

#!/bin/sh
unset DBUS_SESSION_BUS_ADDRESS
unset SESSION_MANAGER
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
/opt/mtl-sys/TurboVNC/bin/tvncconfig -nowin &
RHVER=`cat /etc/redhat-release | awk '{print $7}' | awk -F. '{print $1}'`
if [ $RHVER = '7' ]; then
  mate-session &
# exec startkde
elif [ $RHVER = '6' ]; then
  gnome-session &
fi
exit 0

  • Create a TurboVNC server session

% /opt/mtl-sys/TurboVNC/bin/vncserver :<M> -geometry 1920x1080 -depth 24

where <M> is whatever port you choose (e.g. 28)

  • Exit out of the mtlsim2.mit.edu login session.
  • Configure SecureCRT for a tunneled VNC connection.
    • Choose Connect from the File menu
    • Right click on Sessions and choose New Session
    • Choose Protocol: ssh2 and click Next
    • Enter the hostname: mtlsim2.mit.edu
    • Enter your MTL UNIX username
    • Click Next until you reach the page with Finish on it
    • Change session name to "mtlsim2-TurboVNC"
    • Click Finish
    • Right click on the new session and choose Properties
    • Choose Port Forwarding from the left hand menu
    • Choose Add
    • Enter mtlsim2-TurboVNC for the name
    • Enter local port: 5900 + <M> (where M is typically the same as the VNC server session number ( e.g. 5928 )
    • Enter remote port: 5900 + <N> (where N must be number of the Vncserver session). (e.g. 5928 )
    • Enter the vncviewer client for Application.  You can browse for it and find it in the Windows file system - typically under Program Files or Program Files (x86).  Just locate the VNC client binary and choose it.  We recommend either using either the TigerVNC or TurboVNC client.
    • Enter "localhost:<P>" for the arguments (where P must be the same as M above) (e.g. localhost:28).
    • Click OK until you close out of all dialog boxes.
  • Connect to the new mtlsim2-TurboVNC session that you just created. You should have to enter your MTL UNIX password and then it should automatically run the VNC viewer client and you then enter your VNC password.  At that point, your VNC session should come up.
  • Assuming the VNC session is up and running, open a terminal window and run your usual CAD commands e.g. to run ansysedt do the following:

% use EM
% /opt/mtl-sys/VirtualGL/bin/vglrun ansysedt

Backups

Is my computer being backed up?

All UNIX, Mac and Windows computers that are active and supported in MTL MUMMS should be getting backed up.  If you have a question as to whether or not your computer is being backed up, please send mail to problems@mtl.mit.edu

My machine was backing up, but I am getting an e-mail stating that it is not anymore. What happened?

Are you connecting to the network using a network cable, or via wireless?  If you are using wireless, are you connecting to EECS-MTL-RLE or some other wireless domain?  If you use another wireless domain, such as one of MIT’s, the computer will be on a different subnet and the backup server will not see it.  Wireless connections in general are not as reliable as a wired connection for backing up.  Try using a wired connection if you are exclusively using a wireless connection for your computer while on the MTL network.

If you feel that your computer should be backing up, but you are still getting e-mails saying that it is not, then please send a message to problems@mtl.mit.edu and we can look into the problem.

What information do you need in order to restore my files from backups?

  • The name of the computer on which the files were stored, i.e. your Windows desktop, your UNIX home directory server, etc.
  • The exact path and name of the files.
  • The date from which you would like the files restored.

With that information, we can then see about restoring the files for you from the MTL backups (assuming the computer is being backed up by us).

Computer Setup

I found a computer on a junk pile – can I just starting using it?

The short answer is no. Computers need to be configured properly so that they will work in the MTL computing environment. Without knowing where a computer came from it’s impossible to say what is on it and whether or not it will work at all on the MTL network. In addition, MTL has limited resources and cannot support computers that are too old or ones that have mysterious hardware with hard-to-find software drivers. f you are in need of a computer, check with your supervisor. They may have one available or they may be able to purchase one for you.

Can I set up my computer myself?

As with the question above, computers need to be configured properly so that they will work in the MTL computing environment.  Therefore, it is best if the MTL configures and sets up new computers.

Please let us know if you are going to:

  • Order a new computer.
  • Use an old computer that has been off for a while.
  • Use a computer you found somewhere.

We need to make sure that new computers are set up and patched properly and that old computers are not configured to use network addresses that might already be in use.

We will set up your new computer for you – it will be quicker in the long run.

Why does my laptop need a fixed IP address?

In order to back up MTL laptops, it needs to have a fixed IP address.  In addition, if your laptop is frequently on the MTL network then having a fixed IP address facilitates assisting you with any network-related problems or issues.  The laptop can still get its network address via DHCP.  Our network’s DHCP server will just assign the same address to your laptop each time.

I heard that computers that use DHCP are free. Why should my supervisor pay a computer fee?

The MTL computer fee is a support fee and is not tied directly to the whether or not the computer uses DHCP to obtain its IP address. With that said, all computers that reside regularly on the MTL network should be assigned a fixed IP address whether they obtain it via DHCP or not. Whether or not that computer incurs a fee depends on whether or not that computer is a client of MTL services and is supported.