In DNS, what does MX stand for?
AnswerMail exchange
An MX record names the mail exchange server for a domain.
Tech · Facts & stats
MX facts & stats
7 fact-checked facts about mx records, email delivery and dns basics, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
What does DNS stand for?
AnswerDomain Name System
DNS maps human-readable names to network addresses.
Going deeper
Between two MX records, which one is tried first?
AnswerThe lower preference number
A lower MX preference value means higher priority.
What is the standard port for server-to-server SMTP?
Answer25
Mail servers relay messages to each other on port 25.
SPF policies are published in DNS as which record type?
AnswerTXT
SPF rules are stored in TXT records on the sending domain.
Expert level
Who sent the first networked email in 1971?
AnswerRay Tomlinson
Ray Tomlinson sent it on ARPANET and chose the @ sign for addresses.
DMARC builds on which two email authentication methods?
AnswerSPF and DKIM
DMARC tells receivers how to handle mail that fails SPF and DKIM alignment.
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