mediumMultiple Choice
200-201 Practice Question: During an investigation, an analyst finds that an…
During an investigation, an analyst finds that an internal host has been communicating with a known malicious IP on port 445. Which protocol is most likely involved?
⚠ Common exam trap
Cisco often tests the association of well-known ports with their protocols, and the trap here is that candidates may confuse port 445 with HTTP (80) or RDP (3389) due to common attack narratives, but the specific port 445 uniquely identifies SMB.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
SMB
Port 445 is the default port for Microsoft SMB (Server Message Block) over TCP, used for file sharing, printer sharing, and other network services. Communication with a known malicious IP on this port strongly indicates SMB-based activity, such as exploitation of vulnerabilities like EternalBlue (MS17-010) or unauthorized file access.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
SSH
Why it's wrong here
SSH uses TCP port 22, not 445, so it cannot be the protocol observed. It is tempting because SSH is a common remote-access protocol seen in intrusions; port 445 instead indicates SMB, used for Windows file and printer sharing.
- ✗
RDP
Why it's wrong here
RDP listens on TCP port 3389, not 445, so it does not match the traffic. It is tempting as RDP is a frequent lateral-movement vector; port 445 instead maps to SMB, the protocol exploited by worms such as WannaCry.
- ✓
SMB
Why this is correct
Port 445 carries SMB, the protocol for Windows file and printer sharing. An internal host connecting outward to a known malicious IP on this port indicates SMB-based lateral movement or data exfiltration, matching the investigation's evidence of command-and-control or ransomware staging traffic.
- ✗
HTTP
Why it's wrong here
HTTP defaults to TCP port 80, not 445, so it does not fit the observed traffic. It is tempting because HTTP is ubiquitous and often tunnelled by malware; port 445 instead indicates SMB, commonly abused for lateral movement and ransomware propagation.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-201 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-201 exam.