*Please answer all questions*

1. How many primary keys and how many foreign keys may a table have in a relational database?

2. What factors determine whether a database can contain duplicate records without negative effects, and what are some examples of contexts in which having duplicate records could be a problem?

3. List and briefly describe some administrative policies that can be used with an RDBMS

4. The following table shows a list of pets and their owners that is used by a veterinarian service.

PetName	Type	Breed	DOB	Owner	O_Phone	O-E-mail
Olive	Dog	Poodle	3/27/2007	Thomas	1234567890	tD@abc.com
Teddy	Dog	Labrador	4/2/2008	Paul	1234567890	pD@abc.com
Samson	Cat	Siamese	2/24/2018	Diana	0123456789	dT@abc.com
AJ	Cat	Unknown	8/22/2015	Mary	3456789012	mD@abc.com
Cedro	Cat	Unknown	10/6/2019	Ryan	4567890123	rD@abc.com
Buster	Dog	Alsatian	3/2/2019	Susan	5678901234	sD@abc.com

a. Describe four problems that are likely to occur when using this table

b. Break the table into two tables that fixes the four problems.

5. Assume A, B, C grant certain privileges on the employee table to X, who is in turn grants them to Y, as shown in the following table, with the numerical entries indicating the time of granting.

UserID	Table	Grantor	READ	INSERT	DELETE
X	EMPLOYEE	A	15	15
X	EMPLOYEE	B	20		20
Y	EMPLOYEE	X	25	25	25
X	EMPLOYEE	C	30		30

At time t = 35, B issues the command REVOKE ALL RIGHTS ON Employee FROM X. Which access rights, if any of Y must be revoked, based on the convention defined in section 5.2 of the chapter.

6. Explain the strengths and weaknesses of each of the following firewall deployment scenarios in defending servers, desktop machines, and laptops against network threats.

a. A firewall at the network perimeter.

b. Firewalls on every end host machine.

c. A network perimeter firewall and firewalls on every end host machine

7. SMTP (Simple Mail Transfer Protocol) is the standard protocol for transferring mail between hosts over TCP. A TCP connection is set up between a user agent and a server program. The server listens on TCP port 25 for incoming connection requests. The user end of the connection is on a TCP port number above 1023. Suppose you wish to build a packet filter rule set allowing inbound and outbound SMTP traffic. You generate the following rule set:

a. Describe the effect of each rule.

b. Your host in this example has IP address 172.16.1.1. Someone tries to send e-mail from a remote host with IP address 192.168.3.4. If successful, this generates an SMTP dialogue between the remote user and the SMTP server on your host consisting of SMTP commands and mail. Additionally, assume a user on your host tries to send e-mail to the SMTP server on the remote system. Four typical packets for this scenario are as shown:

packet	Direction	Src Addr	Dest Addr	Protocol	Dest Port	Action
1	In	192.168.3.4	172.16.1.1	TCP	25	?
2	Out	172.16.1.1	192.168.3.4	TCP	1234	?
3	Out	172.16.1.1	192.168.3.4	TCP	25	?
4	In	192.168.3.4	172.16.1.1	TCP	1357	?

Indicate which packets are permitted or denied and which rule is used in each case.

c. Someone from the outside world (10.1.2.3) attempts to open a connection from port 5150 on a remote host to the Web proxy server on port 8080 on one of your local hosts (172.16.3.4) in order to carry out an attack. Typical packets are as follows:

packet	Direction	Src Addr	Dest Addr	Protocol	Dest Port	Action
5	In	10.1.2.3	172.16.3.4	TCP	8080	?
6	Out	172.16.3.4	10.1.2.3	TCP	5150	?

Will the attack succeed? Give details.