Firewall Flashcards
One of the most important tools in OSS
What is the primary function of a firewall?
a) To provide internet access
b) To block all network traffic
c) To monitor and control incoming and outgoing network traffic based on security rules
d) To speed up network connections
Answer:
c) To monitor and control incoming and outgoing network traffic based on security rules
Explanation:
Firewalls are designed to examine network traffic and make decisions to allow, block, or drop it based on a defined set of security rules.
A firewall establishes a barrier between:
a) Two internal networks
b) Secured internal networks and untrusted external networks
c) Hardware and software
d) Different operating systems
Answer:
b) Secured internal networks and untrusted external networks
Explanation:
The primary purpose of a firewall is to create a security boundary between an internal network (like a company’s network) and an external network (like the internet).
Which of the following is NOT a basic security function of a firewall?
a) Packet filtering
b) Application proxy
c) Intrusion detection
d) Network Address Translation (NAT)
Answer:
c) Intrusion detection
Explanation:
Packet filtering and application proxy are basic security functions.
While firewalls can log events, intrusion detection is a separate function, and NAT is a common feature but not a core security function.
What are the three possible actions a firewall can take on network traffic?
a) Allow, block, forward
b) Accept, reject, drop
c) Send, receive, hold
d) Open, close, filter
Answer:
b) Accept, reject, drop
Explanation:
A firewall can “accept” traffic (allow it through), “reject” traffic (block it and send an “unreachable error” message), or “drop” traffic (block it without sending a reply).
In what order does a firewall process network traffic?
a) Apply action, then match rule
b) Random order
c) Match rule, then apply action
d) Apply default policy first
Answer:
c) Match rule, then apply action
Explanation:
The firewall first compares the network traffic against its defined rule set.
Once a matching rule is found, the associated action (accept, reject, or drop) is applied.
What was primarily used for network security before firewalls?
a) Intrusion Detection Systems (IDS)
b) Anti-virus software
c) Access Control Lists (ACLs) on routers
d) Application proxies
Answer:
c) Access Control Lists (ACLs) on routers
Explanation:
Before firewalls, network security was mainly handled by Access Control Lists (ACLs) on routers.
Why were firewalls introduced?
a) ACLs were too complex to configure
b) Routers were too expensive
c) ACLs could not determine the nature of the packet and lacked the capacity to keep out threats
d) To provide Network Address Translation (NAT)
Answer:
c) ACLs could not determine the nature of the packet and lacked the capacity to keep out threats
Explanation:
ACLs have limitations. They cannot analyze the packet’s content or context, and on their own, they are insufficient to fully protect a network from threats.
Which of the following is an advantage of using a firewall?
a) It prevents all security threats
b) It can completely eliminate spam
c) It provides a central point for security and logging
d) It automatically updates its security rules
Answer:
c) It provides a central point for security and logging
Explanation:
Firewalls offer advantages such as acting as an intrusion detection mechanism, providing a central point for monitoring security events and logging traffic.
Which of the following is a limitation of firewalls?
a) They cannot be configured to block specific services
b) They can’t prevent attacks that bypass the firewall
c) They always protect against social engineering
d) They can stop all tunneling attempts
Answer:
b) They can’t prevent attacks that bypass the firewall
Explanation:
Firewalls cannot protect against attacks that don’t go through them, such as internal attacks or attacks that bypass the firewall.
What is port scanning used for in the context of firewalls?
a) To speed up network traffic
b) For investigating the ports used by victims
c) To encrypt network traffic
d) To prevent denial-of-service attacks
Answer:
b) For investigating the ports used by victims
Explanation:
Port scanning is a technique used to discover open ports on a system, which attackers may use to find vulnerabilities.
Which generation of firewalls is characterized by packet filtering?
a) 1st generation
b) 2nd generation
c) 3rd generation
d) Next Generation Firewalls (NGFW)
Answer:
a) 1st generation
Explanation:
Packet filtering firewalls are the first generation of firewall technology.
What is the key characteristic of a stateful inspection firewall?
a) It filters packets based on the application layer.
b) It determines the connection state of packets.
c) It uses proxy servers.
d) It only filters based on IP addresses.
Answer:
b) It determines the connection state of packets.
Explanation:
Stateful inspection firewalls keep track of the state of network connections, making them more efficient than simple packet filters.
Which generation of firewalls operates at the application layer?
a) 1st generation
b) 2nd generation
c) 3rd generation
d) Next Generation Firewalls (NGFW)
Answer:
c) 3rd generation
Explanation:
Application layer firewalls can inspect and filter packets up to the application layer of the OSI model.
What is a characteristic of Next Generation Firewalls (NGFWs)?
a) They only perform packet filtering.
b) They cannot perform SSL/SSH inspection.
c) They include deep packet inspection.
d) They are susceptible to advanced malware attacks.
Answer:
c) They include deep packet inspection.
Explanation:
NGFWs are designed to handle modern threats and include features like deep packet inspection, application inspection, and SSL/SSH inspection.
Which of the following is a characteristic used by firewalls to filter traffic?
a) User’s favorite color
b) IP address and protocol values
c) Time of day only
d) Hostname length
Answer:
b) IP address and protocol values
Explanation:
Firewalls use characteristics like IP addresses and protocol values to filter network traffic.
What is egress filtering?
a) Inspecting incoming network traffic
b) Inspecting outgoing network traffic
c) Filtering traffic based on user identity
d) Filtering traffic based on application protocol
Answer:
b) Inspecting outgoing network traffic
Explanation:
Egress filtering involves inspecting outgoing network traffic to prevent internal users from accessing external networks in an unauthorized manner.
What is ingress filtering?
a) Inspecting outgoing network traffic
b) Inspecting incoming network traffic
c) Filtering traffic based on user identity
d) Filtering traffic based on application protocol
Answer:
b) Inspecting incoming network traffic
Explanation:
Ingress filtering involves inspecting incoming traffic to protect the internal network from external attacks.
What is a critical component in planning and implementing a firewall?
a) The color of the firewall device
b) Specifying a suitable access policy
c) The brand of the firewall
d) The number of network cables
Answer:
b) Specifying a suitable access policy
Explanation:
A well-defined access policy is crucial for a firewall’s effectiveness.
What is the purpose of a firewall’s default policy?
a) To speed up network traffic
b) To explicitly allow all traffic
c) To handle traffic that doesn’t match any specific rule
d) To provide a user-friendly interface
Answer:
c) To handle traffic that doesn’t match any specific rule
Explanation:
The default policy acts as a catch-all for traffic that doesn’t match any of the defined rules.
Which of the following is a type of firewall?
a) Packet filter
b) Host-based firewall
c) Application proxy
d) Stateful inspection firewall
Answer:
b) Host-based firewall
Explanation:
Firewalls can be host-based (installed on individual machines) or network-based (protecting an entire network).
Briefly describe the difference between “reject” and “drop” actions in a firewall.
“Reject” blocks the traffic and sends an “unreachable error” message back to the source,
while “drop” blocks the traffic without sending any response.
Why is a firewall considered an important component of network security?
A firewall is essential to secure the internal network from unauthorized traffic.
Give two examples of how a firewall can be used to control access to services.
Firewalls can block incoming traffic to specific services like POP or SNMP, and they can also block email services to prevent spam.
They can also grant public access to a web server while blocking access to Telnet.
What is a key disadvantage of a firewall regarding internal threats?
Firewalls may not fully protect against internal threats.
They also cannot protect against authorized actions or social engineering.