Thanks to Chris Maltby for the heads up about DMARC. I am trying it out. Unfortunately I'm pretty sure DKIM requires one to own
one's own SMTP server.
On 2020/11/24 11:57 am, Roger Clarke wrote:
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
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--
Kim Holburn
IT Network & Security Consultant
T: +61 2 61402408 M: +61 404072753
mailto:[email protected] aim://kimholburn
skype://kholburn - PGP Public Key on request
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