Cybersecurity Network Security Syllabus

Network Security syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Network Security in Cybersecurity, not a summary of it.

1. 1

   Networking Fundamentals for Security

   4 topics

   • OSI and TCP/IP Models
   • IP Addressing and Subnetting
   • Core Protocols
   • Ports and Services
2. 2

   Network Architecture and Segmentation

   4 topics

   • DMZ and Screened Subnets
   • VLANs and Network Segmentation
   • Network Access Control (NAC)
   • Software-Defined Networking Security
3. 3

   Perimeter Defenses

   3 topics

   • Firewalls
   • Proxies and Reverse Proxies
   • IDS and IPS
4. 4

   Secure Remote Access

   3 topics

   • VPNs
   • Remote Desktop and Jump Servers
   • Secure Access Service Edge (SASE)
5. 5

   Wireless Security

   4 topics

   • Wireless Standards and Threats
   • Wi-Fi Security Protocols
   • Rogue APs and Evil Twin Attacks
   • Bluetooth and RFID Security
6. 6

   Network Attacks

   4 topics

   • Denial of Service and DDoS
   • Man-in-the-Middle and Spoofing
   • DNS Attacks
   • Packet Sniffing and Session Hijacking

Network Security flashcards for Cybersecurity

20 of 61 cards from the Network Security deck — real questions with worked answers.

1. What are the seven layers of the OSI model, in order from Layer 1 to Layer 7?

   Layer 1 Physical, Layer 2 Data Link, Layer 3 Network, Layer 4 Transport, Layer 5 Session, Layer 6 Presentation, Layer 7 Application. Mnemonic: Please Do Not Throw Sausage Pizza Away.

2. How do the four layers of the TCP/IP model map to the OSI model?

   Network Access/Link layer maps to OSI Physical + Data Link; Internet layer maps to OSI Network; Transport layer maps to OSI Transport; Application layer maps to OSI Session + Presentation + Application.

3. At which OSI layers do the following operate: a hub, a switch, and a router?

   A hub operates at Layer 1 (Physical); a switch operates at Layer 2 (Data Link, using MAC addresses); a router operates at Layer 3 (Network, using IP addresses).

4. What is the data unit (PDU) name at the Transport, Network, and Data Link layers?

   Transport layer: segment (TCP) or datagram (UDP); Network layer: packet; Data Link layer: frame. At the Physical layer it is bits.

5. What are the five classful IPv4 address ranges (A through E) by first octet?

   Class A: 0–127; Class B: 128–191; Class C: 192–223; Class D: 224–239 (multicast); Class E: 240–255 (experimental).

6. What are the three private IPv4 address ranges defined by RFC 1918?

   $10.0.0.0/8$, $172.16.0.0/12$, and $192.168.0.0/16$.

7. For an IPv4 subnet with $n$ host bits, what is the formula for the number of usable host addresses?

   $2^{n} - 2$, subtracting the network address and the broadcast address.

8. How many usable hosts and what is the subnet mask for a $/26$ network?

   A $/26$ has 6 host bits, so $2^{6} - 2 = 62$ usable hosts. The subnet mask is $255.255.255.192$.

9. What is the formula for the number of subnets created when you borrow $s$ bits from the host portion?

   $2^{s}$ subnets.

10. What is the CIDR notation and subnet mask for a network that provides exactly 30 usable host addresses?

    You need 5 host bits since $2^{5} - 2 = 30$. This is a $/27$ with subnet mask $255.255.255.224$.

11. What is the APIPA address range and when is it assigned?

    APIPA (Automatic Private IP Addressing) uses $169.254.0.0/16$ and is self-assigned by a host when a DHCP server cannot be reached.

12. What is the size (in bits) of an IPv4 address versus an IPv6 address?

    IPv4 is 32 bits (about $4.3 \times 10^{9}$ addresses); IPv6 is 128 bits (about $3.4 \times 10^{38}$ addresses).

13. What is the loopback address in IPv4 and in IPv6?

    IPv4 loopback is $127.0.0.1$ (block $127.0.0.0/8$); IPv6 loopback is $::1$.

14. Compare TCP and UDP: connection model, reliability, and ordering.

    TCP is connection-oriented, reliable, ordered, with acknowledgments and retransmission. UDP is connectionless, unreliable (best-effort), unordered, with lower overhead and latency.

15. What are the three steps of the TCP three-way handshake?

    1) Client sends SYN; 2) Server replies SYN-ACK; 3) Client sends ACK. The connection is then established.

16. What transport protocol and port does DNS primarily use, and when does it switch?

    DNS uses UDP port 53 for standard queries; it uses TCP port 53 for zone transfers and responses larger than 512 bytes.

17. What are the well-known port numbers for HTTP, HTTPS, FTP (control), and SSH?

    HTTP is TCP 80; HTTPS is TCP 443; FTP control is TCP 21 (data 20); SSH is TCP 22.

18. What ports do SMTP, POP3, and IMAP use (both plaintext and secure)?

    SMTP: 25 (587 for submission); SMTPS: 465. POP3: 110; POP3S: 995. IMAP: 143; IMAPS: 993.

19. What are the three port range categories defined by IANA?

    Well-known ports: $0$–$1023$; Registered ports: $1024$–$49151$; Dynamic/ephemeral/private ports: $49152$–$65535$.

20. What ports are used by RDP, Telnet, SNMP, and LDAP?

    RDP: TCP 3389; Telnet: TCP 23; SNMP: UDP 161 (traps 162); LDAP: 389 (LDAPS: 636).

See more Network Security flashcards →

Planning Network Security for Cybersecurity

Network Security (Cybersecurity) FAQ