Firewalls

Question 1

What two pieces of hardware make up the hardware half of a firewall?

Answer 1

1) a router

2) A blackbox with two NICs

Question 2

What 5 things can firewalls do with traffic?

Answer 2

1) permit
2) deny
3) encrypt
4) decrypt
5) proxy

Question 3

ACLs are first line of defence for a network that is connected to the internet - TRUE or FALSE?

Answer 3

TRUE

Question 4

1) inbound and outbound spoofing
2) Denial of Service TCP SYN attacks
3) DoS Smurf attacks

What can be used to mitigate the above attacks?

Answer 4

ACLs

Question 5

How can ACLs mitigate against the below 3 types of attacks?

1) inbound and outbound spoofing
2) Denial of Service TCP SYN attacks
3) DoS Smurf attacks

Answer 5

1) inbound and outbound spoofing - Filtering ICMP messages inbound and outbound
2) Denial of Service TCP SYN attacks - TCP intercept to address TCP Syn attacks
3) DoS Smurf attacks - Filtering Traceroute

Question 6

ACLs can be used to block routing protocols - TRUE or FALSE?

Answer 6

TRUE

Question 7

An ACL applied to protocols instead of interfaces is known as what?

Answer 7

Distribution List

Question 8

ACLs can categorize and queue packets for applications that require QoS, TRUE or False?

Answer 8

True

Question 9

What could you use to control traffic that may be bound for an expensive backup link?

Answer 9

Using an ACL

Question 10

In dynamic packet filtering, what keeps track of all communicating sessions between stations?

Answer 10

Dynamic State List or State Table

Question 11

Proxies services exchange information between the server on behalf of the host on what layer of the OSI model?

Answer 11

Application

Question 12

What layers of the OSI model can proxies examine?

Answer 12

All layers

Question 13

If you wanted to scan keywords in incoming and outgoing email, what type of proxy would you implement?

Answer 13

SMTP Proxy

Question 14

IP proxies are also known as what?

Answer 14

NAT Proxies

Question 15

What proxy can speed up web surfing?

Answer 15

HTTP Proxy

Question 16

What type of firewall doesn’t care about whether the packet it is examining is stand-alone or part of a bigger message stream?

Answer 16

Stateless firewall

Question 17

Stateless firewalls use less memory than stateful, but stateless firewalls can be quicker once once a new connection is established. TRUE or FALSE

Answer 17

TRUE

Question 18

Statefull firewalls work by using the TCP 3-way handshake but can also keep track of connections using UDP. TRUE or FALSE?

Answer 18

TRUE

Question 19

Firewalls can’t protect against SYN floods. TRUE or FALSE?

Answer 19

FALSE, they can

Question 20

What type of firewall lets you set proxy rules for multiple applications?

Answer 20

Layer 7 firewall

Question 21

What does dynamic packet filtering ensure and on what OSI layer does it operate?

Answer 21

Dynamic packet filtering ensures that the packets forwarded by firewalls match the TCP/UDP sessions initiated by stations inside the network to prevent outsiders hijacking the session. It works at the Transport layer.