[RndTbl] email-receive blacklist?

Colin Stanners cstanners at gmail.com
Thu Apr 29 10:38:41 CDT 2021


I'm afraid that if I understand the situation correctly, the MXVerify
result is not an non-error, it is a real problem, and the likely cause of
your issue.

That serverfault link is unrelated, you are not sending emails only, this
discussion is about your domain receiving email.


On Thu, Apr 29, 2021, 9:16 AM Trevor Cordes <trevor at tecnopolis.ca> wrote:

> On 2021-04-28 Colin Stanners wrote:
> > It's putting the horse before the cart to look into blocklists etc
> > before the e-mail domain is correctly configured...
>
> Thanks for the tool links!  I had thought about DNS issues.  But
> literally no other host that I know of is having problems with me.
>
> > Doing resolver lookup for T=MX domain=``tecnopolis.ca'' Questionable:
> > NO MX DATA: domain=``tecnopolis.ca'' We SIMULATE! Do have at least
> > one MX entry added!
>
> Ya, this is a non-error.
>
>
> https://serverfault.com/questions/947145/is-an-mx-record-required-on-a-domain-to-send-emails-only
>
> My box is just my box, it's the only external-facing box, and as such
> does not require a MX.  However, if some pathologically stupid MTA
> doesn't know the RFC then I guess I'll setup a MX.
>
> > https://mxtoolbox.com/emailhealth/tecnopolis.ca/
> > 7 Problems
> >
> > Category Host Result
> >
> > dmarc tecnopolis.ca No DMARC Record found
> > spf tecnopolis.ca No SPF Record found
>
> This tool also sort of aggressive with its warnings.  Kind of like
> SSL-setup tools moan about using invalid hashes, though 1-3% of the
> hits out there are on old browsers that require them.
>
> I don't have dmarc and spf on purpose.  Surely no MTA would that
> braindead to refuse to *send* to such a server?
>
> > dns tecnopolis.ca SOA Serial Number Format is Invalid
>
> Can a dns client even get the SOA serial?  How does it do that?  Mine
> is set to a normal int within the expected range.  Weird... I'll need
> to verify my server is actually spitting an invalid value out, once I
> figure out how mxtoolbox is reading that info and what value it saw.
>
> > dns tecnopolis.ca SOA Expire Value out of recommended range
>
> Another non-error.  My TTL is 1 week and mxtoolbox thinks it should be
> min 2 weeks.
>
> So useful tools taken with many grains of salt (as are most), at least
> it gives me some ideas and I'll implement one by one and then see if
> Hilton can reach me.
>
> Thanks!
>
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