Unverified50% confidenceFactExact time
The design philosophy of the SMTP protocol is openness and mutual trust: any server can attempt to deliver mail to another server.
1
Sources
50%
Confidence
Long-term
Relevance
10/26/2026
First Seen
Sources
Related Entities
Related Claims
UnverifiedSMTP (Simple Mail Transfer Protocol) is the standard internet protocol for sending email, responsible for delivering mail from a client or application server to the recipient's mail server.80% 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% similarUnverifiedGoing 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.74% similarUnverifiedSMTP is the de facto standard protocol for sending email, with a default plaintext port of 25 and encrypted ports of 465 (SSL) or 587 (STARTTLS).73% similarUnverifiedGmail, combined with SMTP settings, can be configured to send emails using a custom domain email address.72% similar
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