Swarthmore College Department of Computer Science

user rules

We like to maintain liberal policies for users, but we do have a few user rules:

  1. Use the system in good faith. Experiment all you want, but don't try to override existing security. The Computer Science (CS) network is maintained by students, not a professional staff; please be considerate in your use of it.
  2. Give computer science top priority. Someone wishing to use a workstation for a computer science project has priority over anyone who is using the system for non-CS tasks, such as reading news or sending electronic mail. Game playing is allowed but is lowest priority; all academic users should feel free to ask game players to relinquish their machine. The UNIX machines are a computer science lab, not a campus computing facility.
  3. Respect other users' directories. You should not browse through other users' directories unless they have given you specific permission to do so. In other words, /home/user directories are private. To ensure the privacy of your own files, be sure to set the permission flags accordingly (e.g., chmod 700 /home/myusername). Type man chmod for further information or see our chmod help page.
  4. Please protect your account! Even if you think there is nothing valuable in your home directory, keeping your account secure is still critical to the security of the entire system. For example, many hackers first find access to a system they want to break into through a valid user account (such as yours!), and then use that account to do further damage. To protect your account, we ask that you:
    • Use only secure methods of accessing the system. Using secure methods (such as ssh and scp, instead of telnet and ftp) protects your password from network eavesdroppers. Please see connecting to the cs machines for more information on ssh and scp.
    • Use xlock. If you're working in the CS Lab and you need a short break, but don't want to log out, always use xlock to password lock your terminal (just type xlock at the command prompt). Also, make sure you log out completely when you leave the CS Lab (i.e., make sure you see the login screen come back up).
    • Don't share your account. Accounts are for the exclusive use of the account holder. Permitting more than one user on each account is an unacceptable security risk for the whole system. Furthermore, anyone who uses your account will introduce themselves as YOU to potentially millions of people around the world via the Internet.
    • Choose a good password. A good password is one that is at least eight characters long, has upper-case, lower-case, and non-alphabetic characters in it, and can not be found in any dictionary. See choosing good passwords for more information on good passwords. The command for changing your password is passwd.
  5. Please print only CS-related documents on the CS Lab printers. Computer Science has a limited fund for printing supplies. Use the Beardsley public-area printers for non-CS printouts.
  6. Don't take the books out of the lab. A small library of books is kept in the CS Lab for your use; please feel free to read them, but don't take them. This way we know where they are, and students are able to find them when they need them.

If you have any questions about these rules, or general questions about the Computer Science systems, please feel free to contact any of the cs system administrators. You can also send email to local-staff at cs.swarthmore.edu and a sysadmin or CS faculty member will try to answer your questions.