Cisco Certified Network Associate (CCNA) Practice Exam

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Prepare for the Cisco Certified Network Associate (CCNA) Practice Exam. Test your knowledge with our interactive quizzes featuring multiple choice questions, hints, and explanations. Equip yourself for success!

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Which TCP port is used for SMTP?

  1. TCP 25

  2. TCP 53

  3. TCP 80

  4. TCP 100

The correct answer is: TCP 25

SMTP, or Simple Mail Transfer Protocol, is primarily used for sending email messages from a client to a server or between servers. The standard port for SMTP communication is TCP 25. This port is designated for receiving and routing email messages through the internet, making it integral to email functionality. The other options relate to different protocols: TCP 53 is used for DNS (Domain Name System), which translates domain names into IP addresses; TCP 80 is the default port for HTTP (Hypertext Transfer Protocol), facilitating web traffic; and TCP 100 is not a standard port associated with widely-used protocols. Understanding the specific ports and their associated protocols is essential for effective network configuration and management, particularly in scenarios involving email communication.