300-300 · Question #35
Which of the following ports are open by default on a Samba 4 Active Directory Domain Controller? (Choose three.)
The correct answer is B. 138/TCP C. 389/TCP D. 445/TCP. Ports 389/TCP (LDAP), 445/TCP (SMB), and 138/TCP (NetBIOS Datagram) are fundamental to Samba 4 AD DC operation: LDAP handles directory lookups and authentication queries, SMB/445 is the primary protocol for domain communications and file sharing, and NetBIOS/138 supports legacy…
Question
Options
- A443/TCP
- B138/TCP
- C389/TCP
- D445/TCP
- E53/TCP
How the community answered
(43 responses)- A5% (2)
- B88% (38)
- E7% (3)
Explanation
Ports 389/TCP (LDAP), 445/TCP (SMB), and 138/TCP (NetBIOS Datagram) are fundamental to Samba 4 AD DC operation: LDAP handles directory lookups and authentication queries, SMB/445 is the primary protocol for domain communications and file sharing, and NetBIOS/138 supports legacy Windows network browsing. Port 443/TCP (HTTPS) is wrong because Samba 4 does not expose web services by default - that would require an additional role or configuration. Port 53/TCP deserves a note: DNS is critical to AD and does run on the DC, but exam questions in this context often treat DNS as primarily UDP/53, with TCP/53 reserved for zone transfers rather than counted among the "default open" service ports.
Memory tip: Think "LAN Shares Data" - LDAP (389), SMB (445), Datagram/NetBIOS (138). These three represent the directory, the share, and the legacy browse layer that Samba 4 exposes by default.
Heads-up: Be aware that real-world Samba 4 AD DCs also open 53/TCP for DNS. If your exam or course materials emphasize this, that context may override what this particular question tests.
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