P0P3 (Post Office Protocol 3) is a standard protocol for receiving email. By default, to fetch emails, the client connects to the POP3 server on which port?

P0P3 (Post Office Protocol 3) is a standard protocol for receiving email. By default, to fetch emails, the client connects to the POP3 server on which port?

• A. Port 109
• B. Port 110
• C. Port 115
• D. Port 123

Answer: (B)

POP3 retrieves email by establishing a TCP connection to a mail server on a specific port. The standard, non-encrypted POP3 service listens on a fixed port, which is the default for this protocol. That port is widely recognized as the one clients use to fetch mail, enabling commands like USER, PASS, LIST, RETR, and QUIT to be exchanged in plain text. If encryption is used, the secure variant moves to a different well-known port for POP3 over TLS/SSL. The other ports listed correspond to different services: one is associated with an older POP2, another with NTP, and the last isn’t used for mail retrieval. Therefore, the default port for POP3 fetching is the one commonly assigned to POP3 itself.

POP3 retrieves email by establishing a TCP connection to a mail server on a specific port. The standard, non-encrypted POP3 service listens on a fixed port, which is the default for this protocol. That port is widely recognized as the one clients use to fetch mail, enabling commands like USER, PASS, LIST, RETR, and QUIT to be exchanged in plain text. If encryption is used, the secure variant moves to a different well-known port for POP3 over TLS/SSL. The other ports listed correspond to different services: one is associated with an older POP2, another with NTP, and the last isn’t used for mail retrieval. Therefore, the default port for POP3 fetching is the one commonly assigned to POP3 itself.