Emails sent from local web server blocked by PBL

[#1]

Preamble

I have a Raspberry Pi running the PiOS version of Linux and connected to my Plusnet router by an Ethernet cable. I'm running a web server on the RPi. The website is used to offer free I.T. support to my local community, and it includes an appointments booking system called Easy Appointments. The appointments package is working except that, when a customer makes a booking, the confirmation email doesn't arrive.

I believe Easy Appointments uses sendmail. If I use sendmail to compose an email and send it to myself, it reports "rejected due to listing in Spamhaus PBL", although it claims to have sent it successfully. Sample session attached.

Investigation

Looking into this, I see that this is the expected behaviour for Plusnet customers running their own email server. Plusnet simply doesn't allow this, and it's enforced through Spamhaus. Fair enough. So I looked at the Easy Appointments configuration options, and there are various settings there that probably need to be changed. The trouble is, I don't know what values to give the settings.

The relevant settings seem to be:

• smtp_auth (whether to use SMTP AUTH)
• smtp_host
• smtp_user
• smtp_pass
• smtp_crypto (either 'ssl' or 'tls')
• smtp_port

Questions

Do I need to configure this to use SMTP AUTH?

Should I use relay.plus.net as the host?

How can I find my password?

Which port should I use?

And, finally, is this likely to work if I get those settings right, or am I barking up the wrong tree, here?

[#2 · Accepted solution]

@stoneymanor you need the same outgoing server settings that you would normally configure in an email client to send email from a Plusnet email address ( <mailbox>@<account>,plus.com )

Reading between the lines here, you would need to use a PLusnet email address as the from: and  I my guess is you don't have one ? since that facility has not been available to new accounts for some time

If that's the case, then sending via the Plusnet server (relay.plus.net) is not going to work   

[#3]

But configuring to any other email SMTP server which @stoneymanor has legitimate access to should work.

[#4]

If that server permits sending from the address used in the from: , then yes

[#5]

Thanks, @MisterW @Townman 

My fundamental misunderstanding was that I had assumed the Easy Appointments package was behaving like an ordinary email client and would send emails from my usual email address. From that perspective, nothing made sense. So, the answer to my original query was, "Yes, you are barking up the wrong tree!".

I have now created a separate email account for my website and configured the appointments package to use that account's SMTP server. It is now sending email notifications successfully.

This has nothing to do with Plusnet or Policy Block Lists, so this forum is completely the wrong place to ask my question. Sorry for the noise, and thanks for answering a stupid question politely and sensitively.

[#6]

@stoneymanor 

There is no such thing as a stupid question when you do not know.  Until you know, you might post in the wrong place; I did ask the mods to move this to 'Everything else' as it is not a Plusnet mail service issue.

Indeed some systems do run their own SMTP severs ... and that is where things get murky.  Acting as an email message submission client is a far cleaner approach.  That passes all of the complicated stuff (SPF / DKMIN / DMARC) often required these days for many addresses, to somewhere else.

Good luck.