On 05/03/2023 18:47, Nev Young wrote:

I suspect this is a naive question but I'm at a loss how to fix this.

I send emails using thunderbird and msmtp. I post via my ISP's smtp server  (smpt.zen.co.uk)

This has allowed me to send emails to any one as any one. e.g. this has come from alug@nevilley.org.uk

very recently emails sent to gmail users have started to bounce undelivered with the likes of: (email address redacted)

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

##############@gmail.com     host gmail-smtp-in.l.google.com [108.177.15.27]     SMTP error from remote mail server after pipelined end of data:     550-5.7.26 This message does not pass authentication checks (SPF and DKIM both     550-5.7.26 do not pass). SPF check for [nevilley.org.uk] does not pass with ip:     550-5.7.26 [212.23.1.22].To best protect our users from spam, the message has     550-5.7.26 been blocked. Please visit 550-5.7.26https://support.google.com/mail/answer/81126#authentication for more     550 5.7.26 information. p9-20020adfe609000000b002ca647fe919si1349235wrm.527 - gsmtp

Do I need to do something with thunderbird on my PC or is this a problem for Zen? Any help gratefully received. Nev

YES!

I've had to implement this recently.

Google have begun blocking all email without an SPF record

https://support.google.com/mail/answer/81126#authentication

The short story is you should create an SPF record for nevilley.org.uk.

Go to whoever hosts your domain, and add a SPF record and include anyone that can post on your behalf. (Zen).  It is important to ensure you include all IP addresses that can post your mail.  This will usually be defined as a DNS name or some pre-supplied list of ip addresses.  Check with Zen?

You may then want to set up other features too.  I've done DMARK (tells you if your mail's rejected).  I will look at DKIM later ( Certificates to ensure mail not messed with)  Suggest you do SPF, then consider the others.

As I still have the browser windows open, you may find some of these links helpful (or not - this is a bit of a scattergun approach): Define your SPF record https://support.google.com/a/answer/10685031#more-senders

Set up DMARC https://support.google.com/a/answer/10032169#spf-dkim-align

Preventing Spam (etc) with SPF DKIM and DMARC https://support.google.com/a/answer/10583557

Prevent Spoofing with SPF https://support.google.com/a/answer/33786

Incerease security with DKIM https://support.google.com/a/topic/2752442

Dmarc  https://support.google.com/a/topic/2759254

Check your mail settings https://mxtoolbox.com/SuperTool.aspx

Gov UK Check your email settings (actually useful!) https://emailsecuritycheck.service.ncsc.gov.uk/results?domain=nevilley.org.u...

A how to for SPF from 123-reg.  Others would be similar https://www.123-reg.co.uk/support/domains/how-do-i-add-an-spf-record-to-my-d...

***SPF Wizard - helps you craft your SPF Useful! https://www.spfwizard.net/

***SPF Record Explained - USEFUL! https://mailtrap.io/blog/spf-records-explained/

SPF Record checker  https://www.dmarcanalyzer.com/spf/checker/

DMARC checker https://www.dmarcanalyzer.com/dmarc/dmarc-record-check/

Good luck.

If you need help, feel free to email me direct.

Steve