Verified75% confidenceFactExact time
The 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 DMARC
5
Sources
75%
Confidence
Long-term
Relevance
8/9/2026
First Seen
Sources
Noreply邮箱的隐私陷阱：无人回复不等于无人查看
hackernewshackernews8/8/2026
Related Claims
UnverifiedGoing directly through SMTP means sending reputation depends on the domain of the mailbox or mail service used, and the sending domain needs SPF, DKIM and other verification records configured, otherwise mail is more likely to land in the spam folder.79% similarUnverifiedSMTP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75% similarUnverifiedSMTP 协议在设计之初（RFC 821，1982年，由 Jon Postel 撰写）没有考虑身份验证问题，任何人都可以声称自己是任何发件人75% similarVerifiedSPF declares authorized IPs via DNS TXT records, DKIM adds a digital signature to email headers via asymmetric encryption to verify that content has not been tampered with, and DMARC defines handling policies for authentication failures and provides aggregate reports.74% similarUnverifiedDKIM signatures are independent of the transmission path; even if an email is forwarded multiple times, the signature remains valid as long as the signed portion has not been modified, compensating for SPF's shortcomings in forwarding scenarios.74% similar
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