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read the transcript!
there are two important problems in email
From: Kermit @frog.com
To: julia@example.com
- Make sure the message gets to the right recipient. This is what MX records are for.
- Make sure the sender didn’t lie about their From: address. This is what SPF, DKIM, and DMARC records are for.
SPF/DKIM/DMARC are very complicated but we’ll give a tiny incomplete summary.
MX records tell you the mail server for a domain
$ dig +short MX gmail.com
5 gmail-smtp-in.l.google.com.
5 is the priority
google.com is the server’s domain name
copy and paste your MX records
Illustration of a smiling stick figure with curly hair.
person: you’re probably using an email service like Fastmail/Gmail, so just copy the records they tell you to use
tiny guide to SPF/DKIM/DMARC records
SPF: list of allowed sender IP addresses
Example: v=spf1 ip4:2.3.4.5 -all
DKIM: sender’s public key
Example: v=DKIM1; k=rsa; p=MIGFMA0GCSqGSI.......
DMARC: what to do about SPF/DKIM failures
Example: v=DMARC1; p=reject; rua=mailto:dmarc@example.com
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