Historical and Statistical Logging, File Security and Firewalls, Secret and Public Keys - I need the following explained in about 2 paragraphs each the difference between the each of these entities. @ Historical and statistical logging @ File security and firewalls @ Secret and public keys @ Symmetric and asymmetric keys @ Digital certificate and digital postmark

Securities of OSI. - Hello OTA's can anyone describe the type of securities associated and envolved with each level of the Open Systems Interconnect (OSI) Model layers. Thanks Very much.

What is the relation of Linux to UNIX? - In about 2-3 paragraphs to help me better understand What is the relation of Linux to UNIX?

How important is UNIX to the Internet? - In a few paragraphs please give some examples as to the importance UNIX is to the Internet?

What are the advantages and disadvantages of being able to modify UNIX? - What are the advantages and disadvantages of being able to modify UNIX?