I get that, but the question is more whether GCP blocks outbound port 25 or not.
Their docs say they are blocking it: https://cloud.google.com/compute/docs/tutorials/sending-mail yet we see evidence to the contrary. Surely it's a configuration mistake somewhere (?). Maybe someone from Google can shed some light on this. Thanks! On Thursday, 04/09/2025 at 11:25 Michael Peddemors via mailop wrote: Careful.. the list admins don't like us using this list to complain about spam, but yeah.. Anything with a PTR of 1.132.64.34.bc.googleusercontent.com. is suspect, and should be rejected (port 25) ... Standard ruleset for a couple of years.. but even more important, is the number of IPs in those ranges used in email hacking, and BEC Compromise attacks. You might even like to block attempts to other ports by default, and create a 'permitted' acl for IPs in those ranges for legitimate use. On 2025-09-04 07:55, Scott Q. via mailop wrote: > Anyone else seeing an uptick lately of Spam e-mails originating from > these ranges ? > > 34.64.132.0/22 > 35.240.0.0/13 > > Mostly e-mails with: Content-Type: text/plain; charset="iso-2022-jp" > > What's interesting is that GCP has outbound port 25 blocked by default > yet these hosts are able to do direct-to-mx deliveries. > > If anyone from Google is reading this - can you have a look ? > > Thanks! > Scott > > > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://list.mailop.org/listinfo/mailop -- "Catch the Magic of Linux..." ------------------------------------------------------------------------ Michael Peddemors, President/CEO LinuxMagic Inc. Visit us at http://www.linuxmagic.com @linuxmagic A Wizard IT Company - For More Info http://www.wizard.ca "LinuxMagic" a Reg. TradeMark of Wizard Tower TechnoServices Ltd. ------------------------------------------------------------------------ 604-682-0300 Beautiful British Columbia, Canada _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
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