Unverified50% confidenceFactExact time
SMTP协议存在致命缺陷：任何人都可以在邮件的发件人字段填写任意地址
1
Sources
50%
Confidence
Long-term
Relevance
8/12/2026
First Seen
Sources
Related Claims
VerifiedThe SMTP protocol was designed without a built-in authentication mechanism, making email spoofing relatively easy to this day and requiring supplementary verification mechanisms such as SPF, DKIM, and DMARC75% similarUnverifiedEmail sending uses the SMTP protocol, while receiving uses IMAP or the older POP3 protocol.72% similarVerifiedThe SMTP protocol was born in 1982 and is responsible for the sending and relay transmission of emails.71% similarUnverifiedIn the standard SMTP process, when an email is sent to a non-existent address, the receiving server returns a 5xx error code (such as 550 User Unknown) and the sender receives an NDR bounce notification.70% similarUnverifiedGmail's SMTP server address is smtp.gmail.com, port 587.70% similar
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