Computer Networks · Question 17 · Easy
What is the default port number of SMTP, the protocol used to send email between mail servers?
- 25
- 21
- 110
- 53
Answer and explanation
Answer: A. 25
Explanation: SMTP uses TCP port 25. Port 21 is FTP control, 110 is POP3 and 53 is DNS.
Previous: What is the main job of DNS (Domain Name System)? · Next: Which OSI layer is responsible for data representation tasks such as…
Practise computer networks
Try a fresh set of computer networks questions with an explanation after every answer, free and without signing up: Computer Networks practice. Or sit a full placement mock test.
More computer networks questions
- How many redundant (parity) bits does a Hamming code need to correct…
- A TCP sender has a congestion window of 16 MSS, with the whole window in…
- What is the main job of DNS (Domain Name System)?
- Which OSI layer is responsible for data representation tasks such as…
- Which protocol automatically assigns an IP address, subnet mask and default…
- How many bits long is an IPv6 address?
- What is the subnet mask, in dotted-decimal form, for a /28 prefix?
- What is the network address of the host 172.16.45.200/20?
- A Selective Repeat ARQ protocol uses 4-bit sequence numbers. What is the…
- How long does it take to transmit (put on the wire) a 1,500-byte packet on a…
More technical & programming practice
Software Engineering · Cloud & DevOps · GenAI Basics · Pseudo-code · C Programming · Java · Python · Data Structures
LogicWiz Exams home · All practice topics · Placement mock tests · Daily 10 challenge