> Very strange. I can ping all nodes, but port 25 is closed from 3-4
> different IPs/networks in Canada. They must be filtering for some
> reason. If anyone from Google is reading this , can you check what's
> going on ?
Run those different IP addresses through the MultiRBL and compare
with what Google seems to be blocking -- I suspect you'll probably
find that the problematic networks are the ones that have more
listings:
https://multirbl.valli.org/
It's normal for SMTP servers to be filtered against networks that
are threats. We have two private blacklists for each of the SMTP
servers we operate (except for the honeypots) -- one list has IPv4
addresses, and the other had IPv6 addresses. Most of the threats
utilize IPv4, so this is a much larger list. Public DNSBLs add to
these lists dynamically, which makes for a useful combination.
Many years ago we had a few clients use bad ISPs in other countries
a few times over the years. We made exceptions for them, then closed
them after they left those countries. Interestingly, some of those
bad ISPs overbilled these clients, one by quite a lot, and then there
were unauthorized credit card purchases the followed as well.
> ping mx2.smtp.goog
> PING mx2.smtp.goog (216.239.34.151): 56 data bytes
> 64 bytes from 216.239.34.151: icmp_seq=0 ttl=118 time=7.727 ms
> 64 bytes from 216.239.34.151: icmp_seq=1 ttl=118 time=7.738 ms
>
>
>
> nc mx2.smtp.goog 25 -v
> ^C
>
>
> On Friday, 28-08-2026 at 12:37 Bastian Blank via mailop wrote:
>
>
>
>
> On Fri, Aug 28, 2026 at 12:07:16PM -0400, Scott Q. via mailop wrote:
> > Can you guys reach those servers properly ?
>
> | % nc mx1.smtp.goog 25 -v
> | Connection to mx1.smtp.goog (2001:4860:4802:32::97) 25 port
> [tcp/smtp] succeeded!
> | 220 mx.google.com ESMTP ffacd0b85a97d-482fbb287fdsi3510129f8f.207 -
> gsmtp
> | ^C
> | % nc mx2.smtp.goog 25 -v
> | Connection to mx2.smtp.goog (2001:4860:4802:34::97) 25 port
> [tcp/smtp] succeeded!
> | 220 mx.google.com ESMTP ffacd0b85a97d-48351e5704esi145859f8f.261 -
> gsmtp
> | ^C
> | % nc mx3.smtp.goog 25 -v
> | Connection to mx3.smtp.goog (2001:4860:4802:36::97) 25 port
> [tcp/smtp] succeeded!
> | 220 mx.google.com ESMTP ffacd0b85a97d-482fbb550b4si3737625f8f.481 -
> gsmtp
> | ^C
> | % nc mx4.smtp.goog 25 -v
> | Connection to mx4.smtp.goog (2001:4860:4802:38::97) 25 port
> [tcp/smtp] succeeded!
> | 220 mx.google.com ESMTP ffacd0b85a97d-483497c99ccsi173417f8f.479 -
> gsmtp
> | ^C
>
> Bastian
>
> --
> Ahead warp factor one, Mr. Sulu.
> _______________________________________________
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> 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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