CREST Practitioner Security Analyst (CPSA) Practice

What does Port 7 correspond to in network services?

1. File Transfer Protocol

2. Echo or ICMP

3. Domain Name System

4. Remote Job Entry

The correct answer is: Echo or ICMP

Port 7 is associated with the Echo Protocol, which is used to send a message and receive an identical reply, primarily for diagnostic purposes and network testing. It allows a user to verify the integrity of the network by sending data and confirming that it returns intact. This port is not widely used in modern networking due to security concerns, as it can be exploited for reflection attacks, but its primary function remains established as echoing messages back to the sender. The other options correspond to different ports and protocols. File Transfer Protocol operates over port 21, allowing for the transfer of files between a client and server. Domain Name System utilizes port 53 for resolving domain names to IP addresses. Remote Job Entry, which is less common today, typically uses port 5, allowing users to submit jobs to remote systems for processing. Each of these protocols serves distinct purposes and interacts over their respective ports, highlighting the importance of understanding the specific role of port 7 in relation to network services.