pathetic piss kitten (@kitten)

pathetic piss kitten @kitten@elizabeth.cat

there's bots out there that take fediverse usernames and try to send emails to them

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pathetic piss kitten @kitten@elizabeth.cat

either that or just random scrapers that mistake fediverse users for email addresses (maybe even with the @ at the beginning?)

in any case, the do so resolving Webfinger. so, I'm getting emails for @social.elizabeth.cat

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pathetic piss kitten @kitten@elizabeth.cat

I'm also not sure how did they know to send the email to my server. elizabeth.cat has no MX records, so they must be using the A/AAAA record directly

Leah Neukirchen @leah@blahaj.social

@kitten that is by the spec. you can set a null mx if you don't want to receive mail: datatracker.ietf.org/doc/html/rfc7505#section-3

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pathetic piss kitten @kitten@elizabeth.cat

@leah oh wow, TIL

Klaus Frank @agowa338@chaos.social

@kitten @leah

If you don't the spec a Null MX the mailserver specs say it should try sending towards the A/AAAA record when the MX record is absent.

Setting a Null MX basically just serves as a "fail fast" and improves the user experience of not having to wait until all retries are exhausted and delivery ultimately failed. (Which may be 24 to 48 hours later).

(Edit: And it saves you from getting a few connection attempts, but with port scanners these days that is basically minuscule)

erincandescent ⎔ @erincandescent@erincandescent.net

@kitten @leah once upon a time, mx records didn't exist, so the spec has always said fall back to resolving the hostname directly.

you know, as a temporary backwards compatibility measure.

Leah Neukirchen @leah@blahaj.social

@erincandescent @kitten fun fact: SMTP is older than DNS

pathetic piss kitten @kitten@elizabeth.cat

@erincandescent @leah

that must be very old

Leah Neukirchen @leah@blahaj.social

@kitten @erincandescent it's complicated, the first DNS RFC 882 specifies MD and MF records already... but 973/974 which adds MX records describes the fallback to A (or really, an implicit MX record pointing to itself).