Default Ports for Email Server Setup

A junior network technician is setting up a new email server on the company network.

Which of the following default ports should the technician ensure is open on the firewall so the new email server can relay email?

A.

23

B.

25

C.

110

D.

143

B.

The correct answer is B. 25.

Port 25 is the default port used by Simple Mail Transfer Protocol (SMTP) servers to send email messages between mail servers on the internet. When an email message is sent, it is first transmitted from the sender's SMTP server to the recipient's SMTP server. The SMTP server listens on port 25 for incoming messages and uses the same port to send messages to other servers.

To ensure that the new email server can relay email, the junior network technician should make sure that port 25 is open on the firewall. This means that incoming and outgoing traffic on port 25 should be allowed through the firewall to reach the email server.

It is worth noting that some email servers use other ports for sending and receiving email, such as ports 587 or 465. However, port 25 is the default port and is still widely used. Additionally, some ISPs may block port 25 for their residential customers to prevent spam and other types of abuse. In such cases, the email server may need to be configured to use a different port.