Re: ISO service which will return a mail domain as valid or not.

[Rob Berendt <robertowenberendt@xxxxxxxxx>]

Apparently the dns_lookup service fails on some valid entries.  I have some
addresses which receive emails but their domain doesn't have any A or CNAME
records but do have valid MX and NS records.  Their MX records point to
stuff like aspmx.l.google.com.

On Tue, Apr 7, 2026 at 10:26 AM Rob Berendt <robertowenberendt@xxxxxxxxx>
wrote:

> dns_lookup wouldn't be 100% as it doesn't check the endpoint site, let
> alone for the presence of MX records.  However it should catch the
> glaringly obvious typos of the domain, etc.  Which is a help.
>
> On Tue, Apr 7, 2026 at 9:49 AM Sizer, Joseph via MIDRANGE-L <
> midrange-l@xxxxxxxxxxxxxxxxxx> wrote:
>
> > Can you use something like the following to validate the domain and just
> > substitute gmail.com for the customers' domain?
> >
> > SELECT IP_ADDRESS as "IP Address"
> >         FROM table(QSYS2.DNS_LOOKUP('gmail.com'));
> >
> >
> > ________________________________
> > From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> on behalf of
> > Rob Berendt <robertowenberendt@xxxxxxxxx>
> > Sent: Tuesday, April 7, 2026 7:59 AM
> > To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxxxxxxxx>
> > Subject: ISO service which will return a mail domain as valid or not.
> >
> > ________________________________
> >  CAUTION: This email originated from outside of the PENCOR network. Do
> > not click on any links or open attachments unless the sender is known, and
> > the content is verified as safe.
> > ________________________________
> >
> > You send an email and you get a
> > Reason: 5.1.2 - Bad destination host ('000', ['DNS Hard Error looking up
> > aasdfdfsdf9788asfdsf8d87f8d.com (MX): NXDomain'])
> >
> > You decide to get proactive and scrub a file containing all these
> > destination addresses.  You want to run something like
> > select customer_number, customer_name, email_address,
> > email_domain_valid(email_address)
> > from customer_master
> > where email_domain_valid(email_address) = '0'
> >
> > Does anyone have something like the desired email_domain_valid?
> >
> > I can worry about the performance later (like grouping by domain names, a
> > list of whitelisted domain names, etc)  So let's not chase that squirrel.
> > --
> > This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing
> > list
> > To post a message email: MIDRANGE-L@xxxxxxxxxxxxxxxxxx
> > To subscribe, unsubscribe, or change list options,
> > visit:
> > https://urldefense.com/v3/__https://lists.midrange.com/mailman/listinfo/midrange-l__;!!FgubhKw!bJDljpQ-5Foubm5VYMOQ5q1Enkko-FIFhoB3b6DjkIdE55XNYrx_OGg5pB-Y_xdQ1XaW4ahOehNAmA_UrWyTAS28$
> > or email: MIDRANGE-L-request@xxxxxxxxxxxxxxxxxx
> > Before posting, please take a moment to review the archives
> > at
> > https://urldefense.com/v3/__https://archive.midrange.com/midrange-l__;!!FgubhKw!bJDljpQ-5Foubm5VYMOQ5q1Enkko-FIFhoB3b6DjkIdE55XNYrx_OGg5pB-Y_xdQ1XaW4ahOehNAmA_Ure2FIMzL$
> > .
> >
> > Please contact support@xxxxxxxxxxxxxxxxxxxx for any subscription related
> > questions.
> >
> > --
> > This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing
> > list
> > To post a message email: MIDRANGE-L@xxxxxxxxxxxxxxxxxx
> > To subscribe, unsubscribe, or change list options,
> > visit: https://lists.midrange.com/mailman/listinfo/midrange-l
> > or email: MIDRANGE-L-request@xxxxxxxxxxxxxxxxxx
> > Before posting, please take a moment to review the archives
> > at https://archive.midrange.com/midrange-l.
> >
> > Please contact support@xxxxxxxxxxxxxxxxxxxx for any subscription related
> > questions.