Chapter Questions
Read the description of a packet filter for a commercially available router. What features does it offer?
Collect a $\log$ of all traffic entering your site. Analyze the $\log$ to determine the percentage of traffic that arrives from or is destined to a well-known protocol port. Do the results surprise you?
If encryption software is available on your computer, measure the time required to encrypt a 10 Gbyte file, transfer it to another computer, and decrypt it. Compare the result to the time required for the transfer if no encryption is used.
Survey users at your site to determine if they send sensitive information in email. Are users aware that messages are transferred in plain text, and that anyone watching network traffic can see the contents of an email message?
Can a firewall be combined with NAT? What are the consequences?
The military only releases information to those who "need to know." Will such a scheme work for all information in your organization? Why or why not?
Give two reasons why the group of people who administer an organization's security policies should be separate from the group of people who administer the organization's computer and network systems.
Some organizations use firewalls to isolate groups of users intemally. Give examples of ways that internal firewalls can improve network performance and examples of ways internal firewalls can degrade network performance.
If your organization uses IPsec, find out which algorithms are being used. What is the key size?
Can IPsec be used with NAT? Explain.