Microsoft SQL Server (MSSQL) relies on specific ports for its core services, as defined by Microsoft and registered with IANA:
1433/TCP: The default port for the SQL Server Database Engine. Clients connect here for querying databases (e.g., via ODBC or JDBC). It's a well-known port, making it a frequent target for attacks if exposed.
1434/UDP: Used by the SQL Server Browser Service, which listens for incoming requests and redirects clients to the correct port/instance (especially for named instances). It's critical for discovering dynamic ports when 1433 isn't used.
1434/TCP: Less commonly highlighted but used in some configurations, such as dedicated admin connections (DAC) or when the Browser Service responds over TCP for specific instances. While 1433/TCP is the primary engine port, 1434/TCP can be involved in multi-instance setups.
Technical Details:
Ports can be customized (e.g., via SQL Server Configuration Manager), but these are defaults.
Named instances often use dynamic ports (allocated from the ephemeral range), with the Browser Service (1434/UDP) guiding clients to them.
Firewalls must allow these ports for MSSQL to function externally, posing risks if not secured (e.g., brute-force attacks on 1433/TCP).
Security Implications: CNSP likely covers MSSQL port security, as vulnerabilities like SQL Slammer (2003) exploited 1434/UDP misconfigurations. Hardening includes restricting access, changing defaults, and monitoring traffic.
Why other options are incorrect:
A . 1433/TCP, 2433/UDP, 3433/TCP: 2433/UDP and 3433/TCP are not MSSQL standards; they're likely typos or unrelated ports.
C . 1433/TCP, 2433/UDP, 1434/TCP: 2433/UDP is incorrect; 1434/UDP is the Browser Service port.
D . 1533/TCP, 1434/UDP, 2434/TCP: 1533/TCP and 2434/TCP aren't associated with MSSQL; they deviate from documented defaults.
Real-World Context: Tools like netstat -an | find "1433" on Windows confirm MSSQL's port usage during audits.

TCP's three-way handshake, per RFC 793, establishes a connection:
Client → Server: SYN (Synchronize) packet (e.g., port 80).
Server → Client: SYN-ACK (Synchronize-Acknowledge) packet if the port is open and listening.
Client → Server: ACK (Acknowledge) completes the connection.
Scenario: An open TCP port (e.g., 80 for HTTP) with no firewall. When a client sends a SYN to an open port (e.g., via telnet 192.168.1.1 80), the server responds with a SYN-ACK packet, indicating willingness to connect. No firewall means no filtering alters this standard response.
Packet Details:
SYN-ACK: Sets SYN and ACK flags in the TCP header, with a sequence number and acknowledgment number.
Example: Client SYN (Seq=100), Server SYN-ACK (Seq=200, Ack=101).
Security Implications: Open ports responding with SYN-ACK are easily detected (e.g., Nmap "open" state), inviting exploits if unneeded (e.g., Telnet on 23). CNSP likely stresses port minimization and monitoring.
Why other options are incorrect:
A . A FIN and an ACK packet: FIN-ACK closes an established connection, not a response to a new SYN.
B . A SYN packet: SYN initiates a connection from the client, not a server response.
D . A RST and an ACK packet: RST-ACK rejects a connection (e.g., closed port), not an open one.
Real-World Context: SYN-ACK from SSH (22/TCP) confirms a server's presence during reconnaissance.

UDP's connectionless nature means it lacks inherent acknowledgment mechanisms, affecting its port response behavior.
Why B is correct: An open UDP port does not respond unless an application explicitly sends a reply. Without a firewall or application response, the sender receives no feedback, per CNSP scanning guidelines.
Why other options are incorrect:
A: ICMP Port Unreachable indicates a closed port, not an open one.
C: SYN packets are TCP-specific, not UDP.
D: FIN packets are also TCP-specific.

The Active Directory (AD) database on Windows domain controllers contains critical directory information, stored in a specific file format.
Why D is correct: The NTDS.DIT file (NT Directory Services Directory Information Tree) is the Active Directory database file, located in C:\Windows\NTDS\ on domain controllers. It stores all AD objects (users, groups, computers) and schema data in a hierarchical structure. CNSP identifies NTDS.DIT as the key file for AD data extraction in security audits.
Why other options are incorrect:
A . NTDS.DAT: Not a valid AD database file; may be a confusion with other system files.
B . NTDS.MDB: Refers to an older Microsoft Access database format, not used for AD.
C . MSAD.MDB: Not a recognized file for AD; likely a misnomer.

Windows stores password hashes in the SAM (Security Account Manager) file, with a consistent location across 32-bit and 64-bit systems.
Why B is correct: The SAM file resides at C:\Windows\System32\config\SAM, locked during system operation for security. CNSP notes this for credential extraction risks.
Why other options are incorrect:
A: System64 does not exist; System32 is used even on 64-bit systems.
C: C:\System64 is invalid; the path starts with Windows.
D: config\System32 reverses the correct directory structure.