Similar to OpenPGP
DKIM
DomainKeys Identified MailS/MIME
S/MIMESender Policy Framework
Sender Policy Frameworkドメインキー
DomainKeys送信ドメイン認証
Email authenticationBitmessage
BitmessageDMARC
DMARCInbound Port 25 Blocking
Outbound Port 25 Blocking
POP before SMTP
POP before SMTPSender ID
Sender IDSMTP-AUTH
SMTP認証
バウンスメール
Bounce messageバックスキャッター (電子メール)
Backscatter (email)正引きで確認された逆引きDNSエントリ
Forward-confirmed reverse DNSRequest for Comments
Request for CommentsジョークRFC
April Fools' Day Request for CommentsRFC 1149
RFC 1510
RFC 2324
RFC 2550
RFC 2555
Internet Engineering Task Force
Internet Engineering Task ForceCHARGENプロトコル
Character Generator ProtocolDAYTIMEプロトコル
Daytime ProtocolDISCARDプロトコル
Discard ProtocolECHOプロトコル
Echo Protocol