Similar to SMTP-AUTH
送信ドメイン認証
Email authentication
DKIM
DomainKeys Identified Mail
DMARC
DMARC
POP before SMTP
POP before SMTP
Sender Policy Framework
Sender Policy FrameworkBitmessage
Bitmessage
Inbound Port 25 Blocking
OpenPGP
Outbound Port 25 Blocking
S/MIME
S/MIMESender ID
Sender ID
SMTP認証
ドメインキー
DomainKeys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 DNS
Base64
Base64▲2 trendsExchange ActiveSync
Exchange ActiveSync
Internet Message Access Protocol
Internet Message Access ProtocolJSON Meta Application Protocol
JSON Meta Application Protocol
Messaging Application Programming Interface
MAPI
Multipurpose Internet Mail Extensions
MIME
Post Office Protocol
Post Office Protocol
PPAP (セキュリティ)
Quoted-printable
Quoted-printable
Simple Mail Transfer Protocol
Simple Mail Transfer Protocol
SMTPS
SMTPS
STARTTLS
Opportunistic TLS