Stopping spam from my domain name hosted by Plusnet!

[#1]

This happens to me too - on two of my domain names - and usually for a few days at a time maybe once every two or three years. As others have said it's nothing to do with Plusnet - the emails are almost certainly originating from elsewhere.

[#2]

forsterbalcke forwarded 3 examples to me as attachments so I could check the headers. Two were sent from Saudi Arabia and one from Egypt - none through the Plusnet servers.

[#3]

Plusnet have (sort of) admitted they misled me when they said changing my login password would solve the problem:

--------- snip
Dear Mr Forster,
Thanks for getting back to us.
This is a bad update indeed.
Unfortunately if the spammers are somehow spoofing the address then there is very, very little that we are able to do in this situation. We are unable to try and block the emails as they are not being sent using our system.
I apologise, but in this situation, there is nothing that we can do to assist.
Please do not hesitate to get back in touch online at https://portal.plus.net/wizard/?p=search if we can be of any further assistance.
Kind regards,
------------ end
And Barry is right in thinking  I don't have the skills (or the wish) to get to grips with SPF.
So all I shall do is delete the 250 "returns" received and hope the problem will  just (given time)  "go away".
Thanks to all of you and especially to "Jelv" who looked at a couple of mails, confirmed how they were sent and traced their source to Saudi Arabia and Egypt.
Bill

[#4]

Quote from: Barry

One thing you could do is add SPF records for your domain

To my knowledge we can’t add SPF(TXT)  records to Plusnet hosted domains. Or can we?
This is a simple way to publicise genuine mail servers for the domain and enable detection of domain forgeries by any receiving mail system that cares to check.  Whilst it doesn’t stop anyone forgoing a domain for email, it might encourage the spammer to pick on some other non-SPF domain knowing that some receiving mail servers will score it.