Q0: What is the reason for the system upgrade? A0: CSLab is running a very old Linux distribution, RedHat 7.3. It had become increasingly difficult to maintain this distribution because of its age. Many packages were simply not available in binary format and CSLab had to go to great lenghts to still provide basic software. Worst of all is that community support for security patches has been discontinued, meaning that an upgrade MUST be performed asap! Q1: Where/how do I find package X or Y? A1: First try the command: which or slocate If still not found, look in the local directory /pkgs where non-Ubuntu software is installed. There you will find such packages as Matlab, cplex, etc. Q2: My public_html link does not work! How do I edit my web site? A2: For security reasons AIS machines are not permitted to mount the www file systems. The easy solution is to samba mount the home directory as follows. Let's assume the CSLab user name is jdoe. On a CSLab machine (e.g. apps0.cs) jdoe creates a link to his www directory: ln -s /cs/htuser/jdoe/public_html $HOME/ On his AIS machine he creates a directory: mkdir $HOME/sambahome and mounts the CSLab home directory on it smbmount //smb.cs.toronto.edu/jdoe $HOME/sambahome -o username = jdoe All of jdoe's web files will be available for editing in the directory $HOME/sambahome/public_html Q3: I cannot login from outside the CSLab network (e.g. home) directly to my new AIS machine x.ais.sandbox. Why? A3: Your new installation x.ais.sandbox lives on a private subnet whose machines cannot be addressed from outside. This is part of the new POC administered network design. Each POC is responsible for the administration of one or more subnets, but they have to be in a private IP address space (such as ours 192.168.63.xyz). Only machines with a public IP (e.g. 128.100.2.250) is visible from the outside. The only exceptions are made for users with special needs, such as running some server on the workstation. Q4: How do I run VNC server/viewer? A4.0: First of all, we've had some problems with the command 'vncserver' which in the past worked flawlessly. Some paths changed in Ubuntu and the command no longer works. Instead, please use 'vnc4server'. A4.1) If you want to run 'vncviewer' on a CSLab machine (any machine whose domain name ends in toronto.edu, such as apps0.cs.toronto.edu) then: A4.1.1) first run vncserver on your AIS host: vnc4server : where can be a number of your choice, such as 1. A4.1.2) then, on the CSLab computer you can run the following commands: ssh -c blowfish @.ais.sandbox -L 59:localhost:59 -f -N where can be a number between 01 and 99, and is the number you chose in step A4.1.1) and then you can finally start the vncviewer vncviewer localhost: Example: = relu = apps0.cs.toronto.edu = cluster0.ais.sandbox = 01 = 07 then first I run on cluster0.ais.sandbox vncserver :01 and then I run on apps0.cs.toronto.edu: ssh -c blowfish relu@cluster0.ais.sandbox -L 5907:localhost:5901 -f -N vncviewer localhost:07 NB: when you're finished, do not forget on the CSLab server to identify and kill the ssh port forwarding process: ps axw | grep blowfish kill where is identified via the 'ps' command above. Here is a diagram of what happened in the example: ___________ ________________ | | | cluster0.ais | |apps0.cs |port 5907 --> via ssh --> port 5901 | cluster0.ais | |_________| |______________| A4.2) If you are at home and want to connect vncviewer from your home PC to the vnc server on your AIS machine, you need to use one of the CSLab machines as an intermediary: A4.2.1) On the AIS machine start the server: vnc4server : A4.2.2) On the CSLab host run the command: machine: ssh -c blowfish @.ais.sandbox -L :localhost:59 -f -N A4.2.3) On your machine at home run the command: ssh -c blowfish @ -L 59:localhost: -f -N and then you can finally start the vncviewer vncviewer localhost: Example: = relu = apps0.cs.toronto.edu = cluster0.ais.sandbox = 7797 = 01 = 05 First I run on cluster0.ais.sandbox vncserver :01 and then I run on apps0.cs.toronto.edu: ssh -c blowfish relu@cluster0.ais.sandbox -L 7797:localhost:5901 -f -N and on the home PC I run: ssh -c blowfish relu@apps0.cs.toronto.edu -L 5905:localhost:7797 -f -N and vncviewer localhost:05 Here's a diagram of what happened in this example: __________ ___________ ________________ | | | | | | | homepc |5905 -> ssh -> 7797|apps0.cs |7797 -> ssh -> 5901| cluster0.ais | |________| |_________| |______________| Q5: How do I directly ssh to my AIS machine? A5: Unfortunately, a direct connection is not possible to a machine located in a private subnet. But one can setup an ssh tunnel after which all ssh logins will be done via one command. Here's how it works. Let's assume that the AIS machine name is cluster0.ais.sandbox and that the home PC is named homepc. A5.1) First run on cluster0.ais.sandbox the command: ssh -f -N -c blowfish -R 2323:localhost:22 @apps0.cs.toronto.edu Of course you can use any number between 1500 and 9999 instead of 2323, or any other CSLab time sharing server instead of apps0.cs, and use your CSLab user id instead of . A5.2.1) Then on the home machine, if you use Linux, run: ssh -f -N -c blowfish -L 1717:localhost:2323 @apps0.cs.toronto.edu After that you can login directly to the AIS machine by running on your home PC: ssh -p 1717 localhost A5.2.2) Or if you use Windows, you need putty.exe: putty.exe -t -N -L 1717:localhost:2323 @apps0.cs.toronto.edu After that you can login directly to the AIS machine by running on your home PC: putty.exe -P 1717 localhost Q6: I can't start Firefox, it says an instance is already running. What do I do? A6: Run the following commands. cd $HOME/.mozilla/firefox/*.default rm -f lock rm -f .parentlock Do the same in $HOME/.mozilla-thunderbird. Q7: How do I take advantage of CSLab's spam filtering? A7: CSLab has a new and improved spam filtering system. Every incomming message passes through this system and if it is thought to be spam it will contain the string "[PMX:SPAM]" in its Subject: line. If you already use procmail to redirect your messages to different folders, all you need to do is to add the following three lines to your .procmailrc file: :0: * Subject:.*\[PMX:SPAM\] where is just a name for a folder to store what's considered spam messages. If you do not have a .procmailrc file yet, then read on. A7.1: Create a file named .procmailrc in your $HOME directory of your CSLab account, which includes the following: # begin .procmailrc ### set this to the directory where you want to keep all the ### mail folders used by procmail (it is typically the same ### directory as your mail reader keeps its folders) MAILDIR=$HOME/Mail ### set this to the name of the file in which to log procmail's actions LOGFILE=$MAILDIR/procmail.log LOCKEXT=.lock ### Mail which is flagged as spam by CSLab should go to folder ### named Spam :0: * Subject:.*\[PMX:SPAM\] Spam ######################################################################## ### Default: forward mail to the mailbox server to be stored. ### :0 ! ${LOGNAME}+@postbox.cs.toronto.edu # end .procmailrc In order for procmailrc to work we also need to setup a .forward file, also in your $HOME directory of your CSLab account. Therefore, create a file named .forward which contains the following line: CSLABLOGIN-oldmail@oldmail.cs.toronto.edu,, "|IFS=' '&&p=$MAILBIN/bin/procmail&&test -f $p&&exec $p -Yf-||exit 75 #CSLABLOGIN" where you replace the two instances of CSLABLOGIN with your actual CSLab login ID. Q8: How do I use my usb memory stick? A8: Plug it into the usb port. Look around the desktop, you should see a new icon with the volume name. Alternatively, look in the /media/ directory for a new subdirectory with the name of the usb volume (the command 'ls -lt /media' will display the newest subdirectories first). Q9: Printing from the graphical interface in Matlab does not work! Is there a fix? A9: The current situation is as follows. We run two versions of matlab on AIS: Matlab 7sp3 and Matlab 7.3 (aka R2006b). Neither is capable of printing from the user interface. Matlab 7sp3 If a graphical window is opened via the plot command: - File->Print Setup produces the following output: >> java.lang.IllegalArgumentException: services must be non-null and non-empty at javax.print.ServiceUI.printDialog(Unknown Source) at com.mathworks.page.export.printdlg.Printdlg.setVisible(Printdlg.java:435) java.lang.IllegalArgumentException: services must be non-null and non-empty at javax.print.ServiceUI.printDialog(Unknown Source) at com.mathworks.page.export.printdlg.Printdlg.setVisible(Printdlg.java:435) This is a bug in the Linux version of 7sp3 java package. - File->Print simply does not do anything Matlab 7.3 If a graphical window is opened via the plot command: - File->Print brings up a "Printing Failure" dialogue: "There are no properly configured printers on the system" Running strace on the MATLAB process shows that it reads both /etc/printcap and printers.conf, yet it concludes that no printer is properly configured. - this version does not have a File->Print Setup option This bug is not reported any where that I could find on the mathworks.com site. Temporary solution It turns out that only printing from the graphical interface does not work. Command line printing via 'print' or 'print -Pprinter_name' or 'print -deps filename' works on both versions. Q10: How do I ssh into a CSLab server without typing in my password? A10: First check if you already have an ssh key in your account. In subdirectory $HOME/.ssh/ you should find a file named id_rsa.pub; if this file does not exist, it can be created as follows: ssh-keygen -N '' -t rsa Allow ssh-keygen to choose the default file name and location (which will be $HOME/.ssh/id_rsa). Then edit the file $HOME/.ssh/authorized_keys and add one line containing the contents of file $HOME/.ssh/id_rsa.pub Now you should be able to ssh from one machine to another without typing in a password. Q11: There is no /var/mail! How can I read my email? A11: The /var/mail file system cannot be mounted by AIS for privacy reasons. Mail can be read in various ways. * ssh to one of the time sharing servers: http://www.cs.toronto.edu/support/computing_hardware_timesharing.html * using an imap client, such as Thunderbird, pine, etc. Setup according to the following info: http://www.cs.toronto.edu/support/email_pop_imap_smtp.html Q12: How can I get X11 by default everytime I ssh into a computer? A12: On any local computer, type these commands at the command prompt: # if a .ssh directory does not exist, create one mkdir $HOME/.ssh # insert line to forward X11 by default in the ssh config file echo "ForwardX11 yes" >> $HOME/.ssh/config # create an rsa version 2 key, empty password ssh-keygen -N '' -t rsa -f $HOME/.ssh/id_rsa # create an rsa version 1 key, empty password ssh-keygen -N '' -t rsa1 -f $HOME/.ssh/identity # add the public part of both keys to the authorized_keys file cat $HOME/.ssh/id_rsa.pub >> $HOME/.ssh/authorized_keys cat $HOME/.ssh/identity.pub >> $HOME/.ssh/authorized_keys Q14: I have a Windows computer on the RED network. How do I connect to its Remoted Desktop (TM) from home/outside/anywhere? A14: See the following link: http://www.cs.toronto.edu/~pocai/sysadmin/notes/Readme.windows.remotedesktop-sshtunnel.txt Copyright Relu Patrascu, 2006 pocai[at]cs.toronto.edu