Here you will find the steps to create and access the SCS Linux network

The School of Computer Science is running:

• Ubuntu 10.04 Desktop
• has 16 machines on the 'lambda' network (lambda01-16)
• uses Xming for (X11) connections via the SCS Windows Labs
• uses access.scs.carleton.ca as the external gateway; the machines are not visible from outside of the school's network
• user home directories are mounted on all 16 lambda's

Linux Account eligibility:

• Any SCS student taking a computer course that requires linux
• any BCS or SCS graduate student

If you need to create a linux account or simply want to change your linux password (online account system link):

http://www.scs.carleton.ca/webacct/

More information on creating a linux account can be found here: Account Creation Instructions

There are two ways to enter the SCS Lambda Linux network:

1. Graphical access via the SCS Windows labs using the Xming application
2. External gateway access.scs.carleton.ca (non-graphical)

Xming is an X Server that allows you to login to a lambda machine remotely. It's similar to remote desktop in that you get the same login and environment as if you were logged in on the console.

Once you click on the Xming application you will be logged into a chooser. The chooser displays the lambda hosts that are currently available. When you click a particular lambda host you can then login remotely.

The lambda machines are behind the SCS firewall, to access them remotely you need to login to the SCS gateway access.scs.carleton.ca.

To log into the lambda's remotely use your favorite ssh client and lambda:

ssh access.scs.carleton.ca -l jdoe
[jdoe@access ~]$ ssh lambda07
============================================================
 __     Welcome to the SCS    __          __              
/\ \                         /\ \        /\ \             
\ \ \         __      ___ ___\ \ \____   \_\ \     __     
 \ \ \  __  /'__`\  /' __` __`\ \ '__`\  /'_` \  /'__`\   
  \ \ \L\ \/\ \L\.\_/\ \/\ \/\ \ \ \L\ \/\ \L\ \/\ \L\.\_ 
   \ \____/\ \__/.\_\ \_\ \_\ \_\ \_,__/\ \___,_\ \__/.\_\
    \/___/  \/__/\/_/\/_/\/_/\/_/\/___/  \/__,_ /\/__/\/_/
                                   Linux Network

          Questions: support@scs.carleton.ca
       Online: http://www.scs.carleton.ca/nethelp/
============================================================
lambda07:~>

Do you receive the following error?

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
64:1f:1e:50:76:f1:5d:d3:ff:d0:93:4c:e8:73:a9:56.
Please contact your system administrator.
Add correct host key in /home/4user1/hsimpson/.ssh/known_hosts to get rid of this message.
Offending key in /home/4user1/hsimpson/.ssh/known_hosts:21
RSA host key for lambda01 has changed and you have requested strict checking.
Host key verification failed.

This is due to a software and hardware upgrade. What you need to do is ssh to access.scs.carleton.ca and then delete the file ~/.ssh/known_hosts and the ssh key will be re-generated ¹⁾.

There is a process killer installed on the lambda network. It runs once a day and checks for all processes that are:

• not nice'd
• older than 24 hrs

If it meets the above criteria it will kill the process.

The nice command assigns a low priority number to your process. Say you want to run your program called my_program then you can run your program nice'd as follows:

nice my_program

If you already have a running process you can renice it. ²⁾