SK0-004 · Question #749
A company uses a physical server for both email and DNS services. The company recently moved to a cloud-based email platform and no longer needs email to run on this server. After removing the email…
The correct answer is D. Disable port 143. After removing the email application, port 143 (IMAP) should be disabled because it was used exclusively for email retrieval and is no longer needed.
Question
A company uses a physical server for both email and DNS services. The company recently moved to a cloud-based email platform and no longer needs email to run on this server. After removing the email application from the server, which of the following should be done NEXT to further harden the system?
Options
- ADisable port 22
- BDisable port 53
- CDisable port 67
- DDisable port 143
How the community answered
(52 responses)- A13% (7)
- B4% (2)
- C6% (3)
- D77% (40)
Why each option
After removing the email application, port 143 (IMAP) should be disabled because it was used exclusively for email retrieval and is no longer needed.
Port 22 is SSH, still required for secure remote administrative access to the server, so disabling it would cut off legitimate management.
Port 53 is DNS, and the server still hosts DNS services, so disabling it would break name resolution for the network.
Port 67 is DHCP, which was never part of the email service that was removed and is unrelated to this hardening step.
Port 143 is the standard IMAP port, used by email clients to retrieve messages from a mail server. Since the email application has been removed, this port serves no remaining function and leaving it open unnecessarily expands the server's attack surface - disabling unused ports is a core system hardening principle.
Concept tested: Hardening servers by disabling unused service ports
Source: https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml
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