RFC7505 Means Yes, Your Domain Can Refuse to Handle Mail

Posted by zdw on Monday February 22, 2021 @07:44PM
from the bsdly.blogspot.com dept.

https://bsdly.blogspot.com/2021/02/rfc7505-means-yes-your-domain-can.html

( 2 comments | 24 points | on HN )

Re:RFC7505 Means Yes, Your Domain Can Refuse to Handle Mail by buffrr on Tuesday February 23, 2021 @07:01AM (#26236307)

I was curious why a "null MX" is even needed. If there are no MX rrs it would mean that this domain doesn't handle mail, right? It's actually because of the "implicit MX" rule defined in rfc5321[0]. If there are no MX rrs, the SMTP client will still try to use the A or AAAA records to see if there are any SMTP listeners. Adding a null MX "0 ." will cause the delivery to fail immediately.

[0] https://tools.ietf.org/html/rfc5321#section-5

[ Parent | on HN ]

Re:RFC7505 Means Yes, Your Domain Can Refuse to Handle Mail by jsmith99 on Tuesday February 23, 2021 @08:29AM (#26236980)

gov.uk advice is to set up a null dkim record if you don't send email, so you can't be spoofed.

https://news.ycombinator.com/item?id=25210245

[ Parent | on HN ]