Which of the following is NOT an email protocol?
2026
Which of the following is NOT an email protocol?
Answer: C. SQL — ConceptAn application-layer protocol defines rules that network programs use to exchange a particular kind of data. For electronic mail, transfer protocols…
- A.
POP
- B.
SMTP
- C.
SQL
- D.
IMAP
Attempted by 500 students.
Show answer & explanation
Correct answer: C
Concept
An application-layer protocol defines rules that network programs use to exchange a particular kind of data.
For electronic mail, transfer protocols send or relay messages, while access protocols retrieve and manage messages stored on a mail server.
Application
POP and IMAP are mail access protocols, and SMTP is a mail transfer protocol. SQL is a language for working with relational databases rather than a protocol for sending, relaying, or accessing email.
Contrast
POP: retrieves email from a mail server, commonly by downloading messages to a client.
SMTP: submits and relays email between clients and mail servers or between mail servers.
SQL: defines, queries, and modifies data in relational database systems.
IMAP: accesses and manages email while messages remain on the mail server.
Result
Therefore, SQL is the item that is not an email protocol.