The best way to request help is to send email to the appropriate mailing list described below. Your request gets copied to a collection of staff (and in some cases students and faculty) with knowledge in that particular problem area. This is much better than sending email to any one staff member who may be unavailable that day.
You are also welcome to drop in on the compute staff (39-651). Please
note that they may be in the middle of something and so may not be able
to resolve your problem at that instant. The staff may ask that you send
a message to problems@mtl so that we are sure to log and track the problem.
Emergencies
Accounts and Passwords
Network Storage
CAD Issues (but may apply to others as well)
Backups
Computer Setup
Emergencies
How do I contact you in an emergency?
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?
I forgot my password. How do I reset it?
I'm confused. What passwords go with what account?
Network Storage
How do I mount the Z: drive manually?
CAD issues
On UNIX machines, what should the path to network files look like?
It seems that many CAD users are using VNC to connect remotely to the
MTL CAD servers or their own research group servers. Many folks may not be aware that because VNC is not inherently secure, it is highly
recommended to tunnel your VNC connection through SSH. Because of this, we're sending around the following general HOW TO guide that describes how to get VNC set up and to run it securely through SSH. In this example, we'll use mtlsim as the remote server to connect to. 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're using, your 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 at mtl.mit.edu and we'll try to help you.
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Prerequisites:
--------------
(A) You will need a SSH client program installed on your client
computer. e.g. SecureCRT which is freely available from MIT for Windows.
(B) You will need a VNC client viewer program installed on your client
computer. e.g. http://www.realvnc.com/products/free/4.1/download.html
NOTE: If you're client computer is a RedHat 4 or 5 Linux workstation
then you can use the built in VNC and SSH clients that are available.
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NOTE: If you've already run a VNC server within MTL before then you can
probably skip steps 2-4.
1. Login/SSH to mtlsim.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:
>mtlsim2:/homes/bmaloney% vncserver
>
>New 'mtlsim2:34 (bmaloney)' desktop is mtlsim2:34
Where the session number in this example is 34
3. Edit/Create your VNC xstartup file found in ~<your MTL username>/.vnc
Something like this should work:
#!/bin/sh
opers=`uname -s`
if [ $opers = "Linux" ]
then
exec /etc/X11/xinit/xinitrc
else
/usr/dt/bin/dtwm &
/usr/dt/bin/dtterm &
/usr/dt/bin/dtterm &
fi
4. Run the following command to end the session created above:
% vncserver -kill :<session number from above> (for example, :34)
5. Run vncserver again and specify a session number
% vncserver :<N> -localhost -NeverShared=true -DisconnectClients=false
where <N> = a number for your session e.g. 40
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.
(A) Connecting from a Windows desktop client computer
-------------------------------------------------
Run SecureCRT (these notes are specific to SecureCRT 6)
Choose Connect from the File menu
Right click on Sessions and choose New Session
Choose Protocol: ssh2 and click Next
Enter the hostname: mtlsim.mit.edu
Enter your unix username
Click Next until you reach the page with Finish on it
Change session name to "mtlsim-VNC"
Click Finish
Right click on the new session and choose Properties
Choose Port Forwarding from the left hand menu
Choose Add
Enter mtlsim-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).
Enter remote port: 5900 + <N> (where N must be number of the vncserver
session from above).
Enter the vncviewer client for Application e.g.
C:\Program Files (x86)\TightVNC\vncviewer.exe
Enter "localhost:<P>" for the arguments (where P must be the same as M
above).
Click OK until you close out of all dialog boxes.
Highlight the new session and choose 'Connect'
(B) Connecting from a RedHat Linux desktop client computer
------------------------------------------------------
Open up a terminal window and run the following command:
% ssh -L <local port>:localhost:<remote port> -N mtlsim.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 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.
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IMPORTANT NOTE: If you have more than one VNC client session running,
you'll need to choose a different local port for each of them. In other words, if you had separate sessions on mtlcad and mtlsim then one would use 5960 and the other 5961. If do you choose the same local port, they can't both run at the same time.
Backups
Is my machine being backed up?
My machine was backing up, but it isn't anymore. What happened?
What information do you need in order to restore my files from backups?
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 add it to the network and be supported?
Can I set up my computer myself?
Why does my laptop need a permanent IP address?
I heard that computers that use DHCP are free. Why should my supervisor pay a machine fee?
