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Common Issues

How do I access Matlab, Mathematica, Maple, or Splus under BU Linux?

We provide access to various proprietary programs via AFS. The OpenAFS client should already be installed on your BU Linux system, so you just need to type matlab (for example) in a terminal window, and the application will start. As a shortcut, install the usrlocalITbin rpm and put “/usr/local/IT/bin” in your path. (AFS access to matlab is not available off-campus). Matlab and other programs are also available on acs-linux,bu.edu.

How do I connect to matlab on acs-linux?

To run matlab on acs-linux from a linux machine,

  1. Make sure you have an ACS account.
  2. SSH into acs-linux.bu.edu.
  3. Type /usr/local/IT/bin/matlab or simple matlab.

To run matlab on acs-linux from your windows PC, you need to:

  1. Install and configure the program xwin32. (see instructions below)
  2. Use xwin32 to connect directly to acs-linux which will give you a
    terminal window.
  3. In that terminal window, simply type the command “matlab” (or /usr/local/IT/bin/matlab) and you’ll be
    off and running.

We also have instructions to configure xwin32 for the acs servers.

The settings for acs-linux are slightly different from acs, BUT we’d recommend that you FIRST fully set up acs as they instruct, THEN ALSO set up acs-linux with these new settings:

Following the step-by-step instructions for configuring xwin32, make these changes:

Step 3: Instead of ACS, enter: ACS-Linux and then select “ssh” (the directions say “starssh”, but that has now changed to just plain “ssh”)

Step 4: Instead of acs.bu.edu, enter: acs-linux.bu.edu, then click on “Next”

Step 5: Enter your BU login name, but NOT your password.

Step 6: Instead of selecting the command “IBM-AIX”, select “Linux” You should see this command appear in the window: /usr/bin/xterm -ls

If you’ve already set up ACS, then step 7 for registration should be done, and you can just run your ACS-linux connection.

Can I install BU Linux from a flash drive?

Yes.  You must first copy a bootable image onto the USB drive from LINST.BU.EDU.  Unlike images for CDs and DVDs, this image is NOT an ISO file. ( If you are working on a Windows machine, use rawwrite.  For more information, see http://www.chrysocome.net/rawwrite. )  For Mac, Unix, and Linux machines, follow the instructions below:

% ftp linst.bu.edu
(anonymous login accepted)

% cd monde/i386/images

(for 64 bit systems, use: )
% cd monde/x86_64/images

% get diskboot.img

%exit

Insert the USB drive into your system.  The system may automount one or more partitions from the drive.  These all must be unmounted before you do the copy.  To check what’s mounted on your system, use the ‘df’ command.

% df

On my system, the disk partition of the USB drive was automounted. I had to unmount it as follows:

% sudo umount /dev/sda1

Next, one uses the ‘dd’ command to directly copy the image file to the very beginning of the file system:

% sudo dd if=diskboot.img  of=/dev/sda

Note: use the the full drive name, for example here, “/dev/sda”, NOT a particular partition (/dev/sda1, etc.)

Now remove the drive and plug it into the system you want to install. Boot up the system and go into the BIOS setup.  From here, one needs to set the boot priority so the USB drive is first, or at least, before the hard disk drive(s).  The exact details of that depend of the version of BIOS you’re running.  Save and exit the BIOS.  The system should continue booting, find the USB drive, and eventually display the BU Linux installation main menu.  Hit return to begin the install procedure.

Note:  In some circumstances, the hard drive drives may have their labels changed during the installation (from a USB drive).  If you boot up and all you get is a blank grub screen with a flashing cursor, reboot into
the USB drive and type “rescue” at the initial installation screen. From there, one can fix the labels on the hard disk drives.

How do I set up and use wireless networking in BU Linux?

If you installed BU Linux on a computer with built-in wireless networking, or if you’re using a pcmcia card that was already installed in the computer when you installed BU Linux, then wireless networking
should have been set up automatically.

The wireless connection can be brought up and brought down using the “ifup <device-name>” and “ifdown <device-name>” commands by specifying the correct device (usually eth1).

This requires sudo privileges, so it would look like this:

% sudo ifup eth1
or
% sudo ifdown eth1

However, if the device is not already configured, which often happens when you add a wireless pcmcia card to a laptop after you’ve already installed linux, you will need to configure your network files. These are in the directory: /etc/sysconfig/network-scripts/

% cd /etc/sysconfig/network-scripts/

% ls -Fl ifcfg-*
-rw-r–r– 3 root root 236 Aug 20 2008 ifcfg-eth0
-rw-r–r– 1 root root 254 Jul 4 2009 ifcfg-lo

In this case, I have one device, eth0, which is the nic (network interface card/controller) for the network connection that I plug in. You can ignore ifcfg-lo (loopback) for these purposes.

If there were already two nics in the computer, they would be eth0 and eth1, and adding a wireless card would make that eth2. Please adjust accordingly.

To configure the wireless device, I usually just create the file ifcfg-eth1 with any editor (eg. vi, emacs, nedit) using these lines:

DEVICE=eth1
BOOTPROTO=dhcp
ONBOOT=yes
TYPE=Wireless
RATE=Auto

Save your file, then start up your wireless connection with the ifup command:

% sudo ifup eth1

NOTE: If you set ONBOOT=yes, then from now on the wireless connection will come up by itself whenever you boot up your computer. If you don’t leave your pcmcia card in all the time, you might want to set ONBOOT=off
and run the ifup command when you need it.

How do I set up and use vpn in BU Linux?

Once the vpn package (called vpnc) is installed and properly configured, using vpn on BU Linux is as simple as entering the command:

% sudo vpnc-connect

Then replying to each prompt:

  • Password: (This is asking for your local password on your linux system. If you are off campus, you probably will not have access to your kerberos password, so using your local password is necessary.)
  • Enter username for vpn.bu.edu: (This needs your BU Username)
  • Enter password for [username]@vpn.bu.edu: (This needs your BU Kerberos Password)

Once you’ve succesfully done this, you are using the vpn server.

To disconnect, use:

% sudo vpnc-disconnect

However, first let’s make sure that vpnc is installed and properly configured.

To see if it is installed, use the command:

% rpm -q vpnc

that should return something like this:

vpnc-0.3.3-13.el5.centos.bu50.2 (this is the version on Monde, as of Jan 19th, 2010)

If vpnc is not installed yet, simply install it with the command:

% sudo yum install vpnc

Once vpnc is installed, it must be configured.

The configuration files are in the directory: /etc/vpnc/

The vpnc configuration file is named /etc/vpnc/default.conf but this is really just a link to either: oncampus.conf or offcampus.conf

These files are already pre-configured to the proper settings for the BU vpn servers BUT you must make sure that default.conf is linking to the proper file depending on whether your computer is on or off campus.

First check if your settings are set to oncampus or offcampus:

% cd /etc/vpnc

% ls -Fl
lrwxrwxrwx 1 root root 13 Jan 20 13:10 default.conf -> oncampus.conf
-rw-r–r– 1 root root 74 Jan 22 2008 offcampus.conf
-rw-r–r– 1 root root 72 Jan 22 2008 oncampus.conf
-rwxr-xr-x 1 root root 7343 Jan 22 2008 vpnc-script*

As you can see, default.conf is linked to the oncampus vpn server. If you are offcampus, you must change this link using the ln command with the options -fs :

% sudo ln -fs offcampus.conf default.conf

If you check, you will see that now default.conf links to offcampus.conf

% ls -Fl

lrwxrwxrwx 1 root root 24 Jan 20 13:16 default.conf -> offcampus.conf
-rw-r–r– 1 root root 74 Jan 22 2008 offcampus.conf
-rw-r–r– 1 root root 72 Jan 22 2008 oncampus.conf
-rwxr-xr-x 1 root root 7343 Jan 22 2008 vpnc-script*

Once this is properly configured, you are back to where we started, and you can start vpn by simply issuing the command:

% sudo vpnc-connect
(and continuing as described above)

Finally, when you are finished, you can disconnect with:

% sudo vpnc-disconnect

If you are using another type of linux, rather than BU Linux, and would like to know the proper entries for BU’s vpn servers to set up your own configuration files, here they are:

% cat offcampus.conf
IPSec gateway vpn.bu.edu
IPSec ID BostonU
IPSec secret BostonU

% cat oncampus.conf
IPSec gateway vpn.bu.edu
IPSec ID BostonU
IPSec secret BostonU

Firefox stopped working! What now?

My firefox sessions are complaining with an “Assertion Failure”. What”s happening?

Check to see if firefox has been updated. New sessions may have problems until the oldest sessions have been killed. So to be safe, kill all sessions and start firefox again.

Help! I can’t receive mail on my system!

As the saying goes: that’s a feature, not a bug. For security reasons, we’ve configured postfix and sendmail (the programs responsible for transferring e-mail between servers) to be inaccessible from other computers. This is great for most workstations, but obviously isn’t what you want for a mail server.

If you want to receive mail from the Internet on your BU Linux machine, you have to make some modifications to your configuration.

First, make sure incoming mail traffic is allowed through your firewall. You can do this with the GUI firewall configuration tool. Type sudo system-config-securitylevel to launch this program. Note that this is “write only” — it doesn’t read in your previous configuration, so be sure to re-enable any other incoming services you wish to allow.

Then, configure your MTA to listen on the network interface.

For postfix (the default):

  1. Change to the directory /etc/postfix
  2. Edit the file main.cf, and find the line that reads:
    inet_interfaces = localhost
    Change this to be:
    inet_interfaces = all
  3. Save the file, and restart postfix with sudo service postfix restart
  4. Test by typing telnet hostname.bu.edu 25. Typing “quit” will exit out of the test.

For sendmail:

  1. Make sure the sendmail-cf package is installed.
  2. Change to the directory /etc/mail
  3. Edit the file sendmail.mc, and add dnl to the start of the line that reads:
    DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA’)
    This will comment out the option that restricts sendmail access to localhost only.
  4. Save the file, and type sudo make
  5. Add the line sendmail: ALL to the file /etc/hosts.allow
  6. Reload the configuration with sudo service sendmail reload
  7. Test by typing telnet hostname.bu.edu 25. Typing “quit” will exit out of the test.

How do I create a dual boot system?

The simplest way is to start with windows already installed. If you didn’t leave any free space on the hard drive, you will need to shrink the windows partition. This can be done with Partition Magic, or a live Linux CD like Knoppix.

Start the BU Linux installation.

At the partitioning screen, choose “Use free space on selected drives and create default layout”.

After the installation, the bootloader will have an option for “other”, which points to your windows installation. You can edit the title of the entry in /boot/grub/menu.lst.

If you already have both Windows and Linux on your system you can simply add an entry into /boot/grub/menu.lst like the following:

title Windows XP
rootnoverify (hd0,0)
chainloader +1

How can I see which version of BU Linux I am running?

Type: cat /etc/bulinux-release

Help! I finished the install, and I can’t log in!

BU Linux machines can authenticate to the main campus Kerberos servers, but need to have a local database of account information. In some departments, this is provided via LDAP or NIS, but in most cases, you’ll need to set up this yourself.

This is actually easier than it sounds. All you need to do is log in with the root account with the password you created during the installation process. If you are in graphical mode, this should take you immediately to the GUI user account management tool, with which you should find it very easy to add a BU login account which uses your central Kerberos password. If you’re in text mode, simply type sudo add-bu-user username to accomplish the same thing. You can also create a local-only (non-Kerberized) account with a local password.

No matter which course you chose, you may also want to add your account to the wheel group, which will give you administrator (root-equivalent) access via sudo and with the various graphical configuration tools.

When you’ve created your account, exit the GUI tool or log out of the root account, and log back in as yourself.

I installed BU Linux, and now my dual-boot Windows won’t work!

This is a known problem. Luckily, it can be easily corrected by following these steps. Note that although this article is quite old, it has information on preventing the problem from occurring in the first place.

Matlab gives an error about loading shared libraries. What do I do?

If you see an error like this:

/afs/bu.edu/common/IT/matlab-7.X/bin/glnx86/MATLAB:
error while loading shared libraries: libXp.so.6:
cannot open shared object file: No such file or directory

when running Matlab or any other proprietary, binary-only program, check to see if yum (the command-line package management tool used in BU Linux) can find the missing library for you. Type:

sudo yum install libXp.so.6

and yum will search for the library in the BU Linux repository, and if a package can be found that provides it, you will be prompted to install it.

Of course, this can apply to libraries or files other than libXp.so.6 — simply use the appropriate filename in a command similar to the one above.