> Your mailserver
> Your rules
> Are they supposed to care that you´re blocking them?
Those are important points, and a postmaster who does this may
receive technical support calls from their own users who are
expecting eMail from some of those well-known companies in said
blocked ranges.
In an ideal world, iclusion in a widely-used DNSBL is far more
likely to elicit the desired impact of applying pressure to hosting
providers who support spammers and other network-abusing clients.
Unfortuantely, we're not in an ideal world.
> --srs
> ________________________________
> From: mailop <[email protected]> on behalf of ndrs via mailop
> <[email protected]>
> Sent: Tuesday, 29 September 2026 12:56:19
> To: ndrs <[email protected]>
> Cc: [email protected] <[email protected]>
> Subject: Re: [mailop] Attn: Cloudflare, Google, Telegram
>
> Any comment to this?
>
>
> On Saturday, September 19th, 2026 at 5:14 AM, ndrs via mailop
> <[email protected]> wrote:
>
> >
> > > > I have decided to not accept any SMTP connections from the Google cloud
> > > > infrastructure (AS396982).
> > >
> > > I block them completely on my system. There is nothing good inside that
> > > infrastructure.
> > >
> > > Note, that they have two AS assigned tho their cloud infrastructure:
> > > - AS396982
> > > - AS19527
> >
> > How can you do that confidently? Some names in that AS that jump out at me
> > include the following list. Have you confidently documented that no good
> > mail comes out of that AS before blocking? Why not block any host
> > identified as googleusercontent.com instead? Do you service a variety of
> > users who want mail from lots of different places?
> >
> > Uber Technologies, INC
> > Cogent Communications
> > Groupon, Inc.
> > Priceline.com
> > Salesforce, Inc
> > FedEx
> > U.S. Dept. of Health And Human Services
> > The Dun & Bradstreet Corporation
> > Palo Alto Networks, INC
> > S&p Global Inc.
> > US U.S. Securities & Exchange Commission
> > Shopify, Inc.
> > The Home Depot Inc.
> > Federal Deposit Insurance Corporation
> > US Chicago Mercantile Exchange
> > Crowdstrike
> > Mailspike
> > Nokia of America Corporation
> > Ericsson Ab
> > Honeywell International Inc.
> > US Johnson & Johnson
> > Calix, Inc.
> > Dow Networks
> > Credit Karma, Inc.
> > Sendinblue
> > Cisco Webex LLC
> > _______________________________________________
> > mailop mailing list
> > [email protected]
> > https://list.mailop.org/listinfo/mailop
> >
> _______________________________________________
> mailop mailing list
> [email protected]
> https://list.mailop.org/listinfo/mailop
>
--
Postmaster - [email protected]
Randolf Richardson, CNA - [email protected]
Inter-Corporate Computer & Network Services, Inc.
Vancouver, Beautiful British Columbia, Canada
https://www.inter-corporate.com/
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