2

Context:

  • I'm using a server hosted by strato to manage my email, which is called xxxxxxxx.stratoserver.net
  • I've reserved my own domain yyyy.com and manage its DNS at joker
  • I'm using anti-spam provider greenview data

Configuration:

  • The anti-spam provider requires the MX records to be configured to their mail servers
yyyy.com MX 10 yyyy-com.relay1a.spamh.com

  • The anti-spam provider scans the mails and then delivers them to the strato host, using its name xxxxxxxx.stratoserver.net

  • In addition, I have an A record pointing to the strato IP

yyyy.com A 10 123.456.789.123

  • When I send email, the client is configured to send it from [email protected]

  • The client uses the SMTP server of strato at 123.456.789.123 to send the mails. Sending doesn't know anything of the anti-spam provider.

Complication:

Spam filtering works and I receive Email. Email also goes out quite fine. It arrives with most recipients. However, some mail cannot be delivered. The error message I get from remote mail servers is:

550-Requested action not taken:   
mailbox unavailable 550 invalid DNS MX or A/AAAA resource record   
(in reply to MAIL FROM command)

Some research told me, that the MX records are not supposed to point directly to IP addresses, but they're not doing that. My feeling is, the anti-spam configuration is confusing to some receiving mail servers when they do a DNS lookup before delivering the mail. Mail obviously doesn't come from the MX record servers.

I'm stuck, does someone have an idea?

Improve this question
4
  • I don't see either MX or A records on your domain. Are you sure that is your domain and not someone else's? You won't be able to use someone else's domain, obviously.
    – Michael Hampton
    Commented Nov 11, 2018 at 13:59
  • @michael hampton: I've not put my domain in cleartext into the question for privacy reasons. I'm happy to send it to you in a personal message though.
    – kongo09
    Commented Nov 11, 2018 at 19:03
  • Error 550 means "we are not responsible", and this means that the one you wanted to write the mail to, checked your MX - quasi the spam provider - if you have a account on his email server, and he answered NO. Normally you should also send the email via the smtp of the spam provider, and he should feel responsible for emails to your domain. Something of this chain did not happen.
    – user242212
    Commented Dec 7, 2019 at 19:15
  • Unfortunately, the spam provider does not offer SMTP relaying
    – kongo09
    Commented Dec 8, 2019 at 20:52

1 Answer 1

Reset to default
1

I actually had the same issue today. I had a CNAME record for a mail subdomain pointing to the domain which was configured correctly. This configuration also worked fine for the last years until today...

However I solved it by removing the CNAME record and creating an A and AAAA record for my mail subdomain pointing directly to the IP / IPv6. Seems to work for me again. Maybe you are just missing the AAAA record?

Improve this answer
1
  • The server doesn't have an IPv6. I'll add one and see if that changes anything.
    – kongo09
    Commented Dec 8, 2019 at 20:16

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .