220-1201 Practice Question: A customer reports that they cannot send emails…

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

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  25

  Why this is correct

  Port 25 is the standard, unencrypted port designated for the Simple Mail Transfer Protocol (SMTP), which is exclusively used for sending outgoing email messages between mail servers and from email clients to a mail server. If a firewall or network security device is blocking outbound traffic on port 25, an email client will be unable to establish a connection with the outgoing mail server, directly preventing the customer from sending emails. While port 587 (Submission) is now commonly used by clients for authenticated sending, port 25 remains critical for server-to-server email transfer.

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  110

  Why it's wrong here

  Port 110 is exclusively reserved for the Post Office Protocol version 3 (POP3), a protocol designed solely for retrieving incoming email messages from a mail server to an email client. When a client connects via POP3, it typically downloads emails to the local device and often deletes them from the server. Therefore, a blockage on port 110 would only prevent a user from receiving new emails, not from sending them, as POP3 has no function related to outgoing mail.

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  143

  Why it's wrong here

  Port 143 is the default, unencrypted port for the Internet Message Access Protocol (IMAP), which is another protocol used for retrieving and managing incoming email messages on a mail server. Unlike POP3, IMAP allows users to access and synchronize their mailboxes across multiple devices, leaving messages on the server by default. A customer unable to send emails would not be affected by a blocked port 143, as this port's function is strictly for email retrieval and management, not for initiating outbound mail transfers.

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  993

  Why it's wrong here

  Port 993 is the secure version of the Internet Message Access Protocol (IMAP), often referred to as IMAPS, which utilizes SSL/TLS encryption to secure the communication channel for retrieving and managing incoming email. This encrypted port ensures the confidentiality and integrity of email data as it is accessed from the mail server. Since port 993, like its unencrypted counterpart, is dedicated solely to the reception and management of emails, blocking it would only prevent secure email retrieval, having no impact on a user's ability to send outgoing messages.