a not really related fact. I remember reading some RFC, and the sender should tr... | Hacker News

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		tryauuum 7 days ago \| parent \| context \| favorite \| on: Living Dangerously with Claude a not really related fact. I remember reading some RFC, and the sender should try sending to the server specified in A record if there are no MX records present

vidarh 6 days ago | [–]

This sounds like it's an inbound check, as part of spam prevention, by seeing if the sending domain looks legitimate. There are a whole lot of those that are common that are not covered in RFCs.

rstupek 6 days ago | [–]

You are correct that is the expected order of operations

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