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SMTPMTA(Message Transfer Agent)

MUA(Mail User Agent)

SMTP�Protocol

Envelope,�Letter

- Envelopeõ LetterN »ßÜ ó: � ]ó.

Envelope,�Letter

êf� ^ ~Ü f BóB., ì�êÉ MS Z}�  �B ¬ãó.

Anti�Spam

·Ú �ãrV Ñ1a BS^ÊU

Authentication: SPF, Sender ID, DKIM

Reputation: Blacklist, Volume/rate, Uservoting, Bounce mgt, Behavior

Content Filtering: Images, Copy,Construction, Subject, Linkes

Reverse�DNS

- Reverse DNS À� å�

Authentication�:�SPF,�DKIM

- SPFõ DKIMA DNSN îÚ^: S�êÑ Ñè IP É è1a: (U

- HTMLÉ l� !Ö: �Bêff ,ºèN �kÉ l� �VB �BêÜ ØïB Jóº ,�Sk

N »UB (UêÜ Øï� 6�

SPF(Sender�Policy�Framework)- SPF îÚ^Ü .rUB �ÀêÑ SrVB z� ]Ü rV ºè: 0�êÜ DNS îÚ^N ì

6�- SPF bÇ .�¾ / Test Tool

SPF�DNS�Record�Example

ecplazamail.net. IN TXT "v=spf1 ip4:203.242.210.222 -all"

$ dig ecplazamail.net text +short

DKIM(Domain�Key�IdentifiedMail)

- rVN ��É iÛ/ 'º�'B �B- �1aÜ .rU º�B l�êÑ rVS 3����aN .rUɺ �è@Ä?{ �è ��ɺ

ÿ�@Û ��ÜÛ Ñ�: (U Bã

DKIM�DNS�Record�Example

mail._domainkey.ecplazamail.net. IN TXT "v=DKIM1; k=rsa; p=MHwwDQYJKoZIhvcNAQEBBQADawAwaAJhAOMdamAlekOqG/saQ9Pg/ieKxC34FBJjIeV3M413rGPjfObCW2zBz2UKm0ipUtDJLG/efKB+NNvS3OpqIe7UYQqNsGv396eshqpc+uxaCTpvBS6aCgxhFR8RDjyEvIdOeQIDAQAB"

$ dig mail._domainkey.ecplazamail.net text +short

Facebook�email�example

Bounces

What happens when mail could not bedelivered?

- 5xx- Mail Delivery Notification (MDN)

- Delivery Status Report (DSN)

Return�Path

- Return Path is another name for theenvelope sender

- It's the address to which bounces shouldbe sent

- It's usually the same as the From:address

- But can be changed in transit usingschemes like SRS

VERP(Variable�EnvelopeReturn�Paths)

- User replies go to my-list@example.com- Bounces go to bounces-

wez=omniti.com@example.com

Return-Path : <bounces-wez=omniti.com@example.com>From : "my list" <my-list@example.com>To : wez@omniti.comSubject : a message

Welcome to my world!!!

Hard�Bounce

- Recipient email address does not exist- Domain name does not exist

- Recipient email server has completelyblocked delivery

Soft�Bounce

- Mailbox is full(over quota)- Recipient email server is down or offline

- Email message is too large

Contents�Filtering

- Don't use IP address for links(http://193.24.33.1/page/)

- using both text and HTML or text only- The higher the text to link and text to

image ratios, the better- Unsubscribe link: ö^/ ø�Ê

Throttling

Limit send speed per domain

450 too frequent connects from 198.37.147.135, please try again later. (throttled)

ì�Y

- Ñè B&k �B- IP Reputation �B

결!

�ã rV ÑèA third partyÉ W}Ê.

MailChimp12,000 emails/month free

Thank�You�ggg