Re: Touchy subject

> On 13. Nov 2025, at 04:50, Cy Schubert <Cy.Schubert@cschubert.com> wrote:
> 
> On Wed, 12 Nov 2025 09:10:42 -0500
> George Mitchell <george+freebsd@m5p.com> wrote:
> 
>> Please don't reply to the mailing list; email me personally.  In fact,
>> I apologize for even raising this subject on a FreeBSD mailing list,
>> and I won't bring it up again.
>> 
>> I'm on the verge of blocking all emails from machines whose reverse
>> IPs resolve to googleusercontent.com.  I'm a small enough presence on
>> the net that Google won't even notice, but the spam is getting way
>> out of hand.
>> 
>> Is this something anyone else has considered?            -- George

I maintain my own “blocklist”:

When I see a spam that made it through the spamassassin, I look into the headers,
find the relay through which it came to my boxes, look into whois database and
block either that IP or the whole netblock. Also I feed the offending e-mail
to sa-learn —spam.

This table is then made available via https so all the mail servers (some really big ones)
that I administer, can download and use it as well.

For quite a long time I also had a “delay 20” in smtpd_recipient_restrictions,
as an “less intrusive” alternative to greylisting.

> 
> I deny IP sending IP addresses based on SPF. postfix-policyd-spf-perl
> implements SPF for postfix. If you're a sendmail user you should look
> into the mail/spfmilter port.

This is a good idea.

—
Juraj Lutter
otis@FreeBSD.org