Good morning Ralph. Ralph Corderoy wrote in <[email protected]>: |Hi Rachel, | |There's discussion on the [email protected] mailing list about a |support reply from neverbounce.com. (Please keep |[email protected] CC'd.) ... |For delivering [email protected], the DNS entries are | | $ dig +nocomment @8.8.8.8 lists.sdaoden.eu. | | ; <<>> DiG 9.13.7 <<>> +nocomment @8.8.8.8 lists.sdaoden.eu. | ; (1 server found) | ;; global options: +cmd | ;lists.sdaoden.eu. IN A | lists.sdaoden.eu. 14399 IN CNAME sdaoden.eu. | sdaoden.eu. 14399 IN A 217.144.132.164 | ;; Query time: 52 msec | ;; SERVER: 8.8.8.8#53(8.8.8.8) | ;; WHEN: Wed Mar 27 10:12:48 GMT 2019 | ;; MSG SIZE rcvd: 75 | | $ | |RFC 5321, Simple Mail Transfer Protocol, says | | https://tools.ietf.org/html/rfc5321#section-5 | | The lookup first attempts to locate an MX record associated with the | name. If a CNAME record is found, the resulting name is processed | as if it were the initial name. | |lists.sdaoden.eu has no MX record, but does have a CNAME for sdaoden.eu |and so that should be then treated as the initial name. | |sdaoden.eu has no MX record. This is also covered in that section of |RFC 5321: | | If an empty list of MXs is returned, the address is treated as if it | was associated with an implicit MX RR, with a preference of 0, | pointing to that host. | |Thus sdaoden.eu is to be treated as an MX RR record. A lookup on that |gives the A record for 217.144.132.164. That IP address is the one to |connect to. | |Perhaps NeverBounce are getting confused with this part: | | When a domain name associated with an MX RR is looked up and the | associated data field obtained, the data field of that response MUST | contain a domain name. That domain name, when queried, MUST return | at least one address record (e.g., A or AAAA RR) that gives the IP | address of the SMTP server to which the message should be directed. | Any other response, specifically including a value that will return | a CNAME record when queried, lies outside the scope of this | Standard. | |So an MX RR's value can't resolve to a CNAME, but the implicit one above |doesn't, it gives an A. It's perfectly valid, and explicitly covered |above, for the lookup desiring an MX to find a CNAME. | |Please can you re-appraise NeverBounce's RFC compliance. Thanks. | |Steffen, don't change you DNS configuration. It's correct and helps |flush out problems like this that may be affecting NeverBounce's |treatment of other addresses.
Thank you for diving into the standards, Ralph. I even did it false all the time, did i. Ciao! --steffen | |Der Kragenbaer, The moon bear, |der holt sich munter he cheerfully and one by one |einen nach dem anderen runter wa.ks himself off |(By Robert Gernhardt)
