Visit the University's virus site.
They have tests you can run to check the security
of your computer system, plus a lot of discussion of security
issues. The sites www.privacy.net/analyze/ (this one shows you what information your web browser divulges about you) and
www.robertgraham.com/pubs/ are also useful.
Also, use ssh (for secure shell) instead of telnet (if ssh is
available), to log into a remote computer:
type "ssh email@example.com" at the prompt of a terminal