Gmail again!

[#1]

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@pvmb wrote:

One possible explanation could be that there IS a lot of SPAM coming from Plusnet email addresses...

Some people who have complained of receiving a lot of SPAM over recent months have said some came from their own email address. Then again, some of the more dodgy 'recommendations' on here about the settings for client email software make me wonder if some people's Plusnet account passwords have been compromised, not just their email addresses.

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Um...

[#2]

It's the Plusnet 31.***.***.*** IP range where there is a problem - based on Spamhaus checks.

But lookee here - what's going on, 'EE'?

% Abuse contact for '31.125.0.0 - 31.125.255.255' is '[email protected]'

inetnum: 31.125.0.0 - 31.125.255.255
netname: EE4
descr: Plusnet Broadband
country: GB

 Perhaps it's all those people with ex Plusnet landline phones getting their own back? 😎

[#3]

I sent some test emails from my plusnet email to my gmail account last night.

There was a delay of several hours before they arrived - in my gmail spam box.

I have marked them as 'not spam' in gmail and will monitor to see if that setting sticks.. .

As far as I know I have fully migrated to Greenby but I am in the odd situation of still being a Plusnet customer while I await transfer to another Broadband provider. I just hope the email will still work after my plusnet account is finally closed. Not that I have much faith in Greenby...

[#4]

Jesus [-Censored-] Christ! It's a shambles out there...[-Censored-]

So I patiently composed a request/complaint form to Spamhaus about the SBL blocking: My name, my email address, my IP, my domain name, carefully listed 1 to 5 comments.

SEND

Submission Error
captcha validation error

Yet I PASSED the [-Censored-] CAPTCHA to get onto the Spamhaus site in the first [-Censored-] place!

No wonder nothing works... 😠

Moderator's note by Mike (Mav): Avoidance of swear filter edited as per Forum rules.

[#5]

...Well, that's one more email "successfully delivered" - very quickly.  😶

[#6]

Friday 3/7/2026  17:08

host alt1.gmail-smtp-in.l.google.com[172.253.152.26]
    said: 421-4.7.28 Gmail has detected an unusual rate of mail originating
    from your SPF 421-4.7.28 domain [<xxx>.plus.com      35]. To protect
    our users from 421-4.7.28 spam, mail sent from your domain has been
    temporarily rate limited. 421-4.7.28 For more information, go to 421-4.7.28

Some you win and some you don't...

Three emails to this same recipient in the last two days, two got through

[#7]

Are you seeing the Public IP of your connection rejected as blacklisted when sending emails ?

That would be very odd as the SPF entries for your email address are the IPs the receiving server should see, this is assuming your email address does match the SMTP server being used.

[#8]

@offscotland @pvmb and others

Do you get the 421-4.7.28 rejection immediately? Mine are always received after 70 minutes which makes me wonder whether in the meantime there have been umpteen retries for whatever reason, resulting in the gmail server eventually perceiving that it is being bombarded by spam!

[#9]

Last month Greenby's SMTP servers enabled DKIM strictly aligned with SPF i.e. at the <subdomain>.plus.com level
that really improved delivery for our email accounts.

[#10]

Has that been done for everyone or are they working their way through the sub-domains (on an undisclosed timescale as always)?

[#11]

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@PhilipHeyes wrote:

Last month Greenby's SMTP servers enabled DKIM strictly aligned with SPF i.e. at the <subdomain>.plus.com level
that really improved delivery for our email accounts.

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And yet... It seemingly hasn't! Getting to the bottom of this nonsense really is complicated by the fact that you can never tell what is really going on or what is really happening. Sure, the rejection message 'tells' you - but what does it actually mean? Does it literally mean what is says? If I take it that way then there are really stupid contradictions:

My domain <User>.plus.com is CLEAN - as it should be

My IP address - for <User>.plus.com is on a block list.

But I am on a static IP, so my IP address IS my domain name and vice versa.

Plus, it's "normal" for an ordinary person with an IP network address to be on such an address block list (SPAM control) - doesn't stop them sending emails that go via an authenticated SMTP host mailer - just like I am doing. Only a problem if you are trying to send email "direct to the Internet" from a mailer host - just like I am NOT doing.

So...

I have started wondering if reversing my previous request to Plusnet about stopping reverse DNS requests of my IP address would have any effect. I have no idea.

[#12]

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@abitpedantic wrote:

@offscotland @pvmb and others

Do you get the 421-4.7.28 rejection immediately? Mine are always received after 70 minutes which makes me wonder whether in the meantime there have been umpteen retries for whatever reason, resulting in the gmail server eventually perceiving that it is being bombarded by spam!

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It's an 'Interesting Theory'! IMO anything meaningful is worth considering at this stage.

The error messages from Gmail do come back after quite some elapsed time, certainly not 'immediately'. But I can't say how long that time is. I could try sending more mail to Gmail as part of testing this. Possibly risking ending up on a permanent BAN list for continually sending out 'SPAM'. 🙄

Why is this starting to remind me of being on ADSL? 

[#13]

@pvmb 

The rejection that you are reporting resembles what we encountered via a Plusnet hosted SMTP server
with the DKIM signature at the plus.com root level.

[#14]

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Submission Error
captcha validation error

Yet I PASSED the [-Censored-] CAPTCHA to get onto the Spamhaus site in the first [-Censored-] place!

No wonder nothing works... 😠

Just occurred to me that this is not literally true, in fact it's literally untrue!

"Yet I PASSED the [-Censored-] CAPTCHA to get onto the Spamhaus site in the first [-Censored-] place!"

I got onto the Spamhaus site via one of those, pretty frequent these days, "Performing security verification..." from Cloudflare. Which I always seem to pass. My network IP must be OK then? 🙄

I got the Captcha error message when I tried to send my form on the Spamhaus site. But I saw no Captcha! So I think this still applies:

"No wonder nothing works... 😠"

Not to mention why abuse on my IP network zone should be reported to 'EE' - "[email protected]"

Moderator's note by Mike (Mav): Avoidance of swear filter edited as per Forum rules.

[#15]

@abitpedantic 

All of this depends on using a Greenby hosted SMTP server. i.e one that has an IP like 91.x.x.x

I can only comment with certainty on our ex-Plusnet account in the format : <name>@<subdomain>.plus.com
as that is the only one I can test.

To check for your own account  :

1) Greenby portal, has DKIM been enabled for you in the Email >> Settings ?

2) Try : https://mxtoolbox.com/dkim.aspx   

Domain is the bold bit of the email address  yourname@domain.co.uk

Selector : en   

3) Send an email from your a/c to an email address that is not related to Plusnet and inspect the email header / source;
sent to a BT Internet a/c we see : 


Authentication-Results: btinternet.com;
    dmarc=pass header.from=<account>.plus.com;
    dkim=pass;
    spf=none smtp.helo=arabellina.gateway.enmail.co;
    spf=pass smtp.mailfrom=<account>.plus.com;
    arc=none smtp.remote-ip=213.5.178.136


DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=<account>.plus.com; s=en; t=1781523375; bh=fCrnRBJNx78t4MmJrwIG1HeTlsKTuB+CO+YYP8AcExM=;