Many thanks to the several people who pointed me to the SPF entry! Chris Maltby's explanation (all-but) nailed the problem.
Changing the SPF entry to ip4:103.27.32.0/24 fixed Yahoo. But my Rocketmail mate still gets my messages thrown into Junk. VentraIP responded, and recommended a different SPF entry: v=spf1 +a +mx +include:spf.hostingplatform.net.au ~all That also appears to work for Yahoo, but also not for Rocketmail. I've looked into DMARC and inserted: TXT v=DMARC1; p=none; [email protected] That ought to generate a rejection-message that might help with debugging; but it hasn't so far. I was vaguely been aware of SPF and DMARC but had never looked at them. Only 0.1% of my correspondents use Rocketmail, and he's said he also found a telco invoice in his Junk-folder this morning ... Thanks Chris and others! _______________ WAS: TXT v=spf1 ip4:103.27.32.5 +include:retailspf.smtp.com ?all CHANGED TO: TXT v=spf1 ip4:103.27.32.0/24 +mx +a ~all The old one says to trust email that comes from a specific IP-address. The new one says to trust it if it comes from a range of IP-addresses. The SMTP-server operator has big volumes, and uses multiple addresses. CHANGED AGAIN TO: v=spf1 +a +mx +include:spf.hostingplatform.net.au ~all Both new entries *ought* to leave no clues for Rocketmail's Artificial Stupidity to trip over - although the first works only if ISP's wholesale provider stays within that range of IP-addresses. Networked business topologies are *so* much more efficient, right?? _______________________ On 22/11/20 1:12 pm, Chris Maltby wrote: > I'm not sure that your xamax.com.au SPF details are good. > > xamax.com.au: "v=spf1 *ip4:103.27.32.5* +include:retailspf.smtp.com ?all" > retailspf.smtp.com: "v=spf1 ip4:192.40.160.0/19 ip4:74.91.80.0/20 ~all" > > but the sending address at syd.hostingplatform.net.au is 103.27.32.232. > You could try changing the ip4:103.27.32.5 to ip4:103.27.32.0/24. > > You might also want to set up a DMARC record so that you can receive > reports of messages that fail SPF/DKIM/ARC checks. > > Yahoo is one of the fussiest, but also seems to permit the most real spam... > > Chris > > On 21/11/2020 7:14 am, Roger Clarke wrote: >> If anyone can point me to relevant sources to help me understand and >> address the following problem, I'd be very appreciative! _______________________ Roger Clarke mailto:[email protected] T: +61 2 6288 6916 http://www.xamax.com.au http://www.rogerclarke.com Xamax Consultancy Pty Ltd 78 Sidaway St, Chapman ACT 2611 AUSTRALIA Visiting Professor in the Faculty of Law University of N.S.W. Visiting Professor in Computer Science Australian National University _______________________________________________ Link mailing list [email protected] http://mailman.anu.edu.au/mailman/listinfo/link
