The not so simple mail transport protocol
summary
Explains how SMTP lacks authorization and shows concrete fixes: SPF via DNS TXT records, examples of records and the real caveats such as SPF limits: 10 DNS lookups and that SPF breaks forwarding; shows DKIM key generation with openssl 2048-bit key, selector DNS record format, and SwiftMailer/PHPMailer signer integration; covers DMARC policies (none/quarantine/reject), alignment modes relaxed/strict, reporting as XML aggregate files and the rollout advice start DMARC at pct=1% so you can validate before enforcing.
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chapters (31)
- 0:00Intro
- 0:54Collector of elePHPants
- 3:08SMTP is old
- 4:05what is this
- 5:28how SMTP works
- 7:09The Internet Message
- 7:51Sending a message using SMTP
- 8:10The envelope
- 8:54The message
- 9:24Meanwhile on the server....
- 11:30No authorization
- 13:43How SPF works
- 14:46Your first SPF record
- 16:37Qualifiers
- 16:49Limitations
- 17:44Creating our own complete SPF configuration Allow the MX's to send email, denying all other systems (use--all when testing)
- 18:38Creating our own SPF configuration
- 19:31Best practices when implementing SPF
- 21:39Resources
- 21:54Recap
- 23:18How DKIM works
- 24:43Generate a keypair • Generate a keypair (you should use a 2048 bit key)
- 26:27How to use DKIM
- 27:18sending a signed message using swiftmailer
- 28:31Understanding the signature
- 29:35Advantages of DKIM
- 30:05How DMARC works
- 32:05Creating a DMARC record
- 33:37Alignment
- 35:05Advantages of DMARC
- 36:49Takeaways
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