On 2025-06-26 at 04:33:14 UTC-0400 (Thu, 26 Jun 2025 10:33:14 +0200)
Support 3Hound via mailop <supp...@3hound.com>
is rumored to have said:
Dear list,
is it fair/correct to check the existence of a mailbox for about 30/50
mail addresses/day?
As described, no, but you are unlikely to be noticed.
Also: there is no way to definitively confirm the deliverability of any
address without actually delivering mail to it and receiving a
confirming action like a reply or requesting a unique URL.
They quite always will be present unless misspelled or typo that may
be a couple in a month.
Which is why the collector of an email address MUST verify it AT THAT
TIME.
We must RSET and then QUIT every the smtp connection just after the
RCPT TO answer because we must check the data but we cannot contact
these users.
If you do that to any system I administer, you will find your IPs
blocked and ou might get a complaint to the upstream ISP to whom the IP
is registered. Or the block may be silent and permanent until a customer
notices and complains, which happens roughly NEVER.
We actually are checking the domain and MX existence.
Which is entirely fine, as it does not impose any responsibility on the
owners of forged or misspelled domains. That should be done at the time
of collection, before accepting the email address at all.
Do you think that we may be blocked or reputation decreased if we
activate this kind of recipient checking process?
Absolutely yes. It's obnoxious.
Note: we are not going to send them any e-mail also after this
process, this isn't a database verification but a paper collecting
process.
Collecting email addresses on paper is worthless. You might as well
generate the addresses randomly.
Long explanation (preventing the double opt-in and bad-collecting
process objections):
Our customer collect e-mail addresses written over *paper signed
contracts*
Those addresses are USELESS. Doing anything with them puts you at
reputational risk. Your customer needs to redesign their processes.
--
Bill Cole
b...@scconsult.com or billc...@apache.org
(AKA @grumpybozo@toad.social and many *@billmail.scconsult.com
addresses)
Not Currently Available For Hire
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