I think I figured out why the original bounced -- there are return characters, "\n" in the Subject line. I looked at the mail logs on my server and saw that.
The bounce message came from the server at altprdrgo002.altice.prod.cloud.openwave.ai, but that still doesn't tell me much. Thanks, Ken On Sat, Oct 11, 2025 at 7:42 AM Benny Pedersen via mailop <[email protected]> wrote: > Rainer Daeschler via mailop skrev den 2025-10-11 10:41: > > Hi Ken, > > > >> Please reply to <Postmaster@ {mx.internal}> > >> if you feel this message to be in error. > >> > >> The original message has been removed from the bounce message. > >> > >> Reporting-MTA: dns; altprdfep009. {mx.internal} > >> Arrival-Date: Thu, 9 Oct 2025 08:02:03 -0400 > >> Received-From-MTA: dns; altprdrgi011.altice.prod.cloud.openwave.ai > >> [1] ( {10.33.66.227}) > >> Content-Transfer-Encoding: 7bit > >> … > >> Diagnostic-Code: smtp; 550 5.7.1 Spam detected by content scanner. > >> Message rejected > > {mx.internal} = none existent domain > > {10.33.66.227} = private IP address, not the IP from > > altprdrgi011.altice.prod.cloud.openwave.ai. > > > > No wonder it's considered spam. > > :-) > > postfix can reject rfc 1918 mx hosts via cidr maps > > # cat main.cf > > smtpd_sender_restrictions = ... check_sender_mx_access > cidr:/etc/postfix/rfc1918.cidr > > # cat rfc1918.cidr > > Here are some other things you can do with check_*_mx_access (this is > a "cidr:" map type): > > 0.0.0.0/8 REJECT Domain MX in broadcast network > 10.0.0.0/8 REJECT Domain MX in RFC 1918 private network > 127.0.0.0/8 REJECT Domain MX in loopback network > 169.254.0.0/16 REJECT Domain MX in link local network > 172.16.0.0/12 REJECT Domain MX in RFC 1918 private network > 192.0.2.0/24 REJECT Domain MX in TEST-NET network > 192.168.0/16 REJECT Domain MX in RFC 1918 private network > 224.0.0.0/4 REJECT Domain MX in class D multicast network > 240.0.0.0/5 REJECT Domain MX in class E reserved network > 248.0.0.0/5 REJECT Domain MX in reserved network > > pretty safe if remote is ipv6 :) > > in that case add ipv6 to cidr map > _______________________________________________ > mailop mailing list > [email protected] > https://list.mailop.org/listinfo/mailop >
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