Did I send 1000+ spam emails this morning?
On average I receive around 20-30 spam emails daily, with the usual subject matters that try and entice me to buy something I don't need, expand a part of my body or watch something I don't want to see. Occasionally mixed in with them I get some "mail undeliverable", "postmaster notification" or "mailer daemon" etc, which I disregard along with all the other spam.
This morning, however, I clicked Thunderbird's get-mail button only to see 1379 emails waiting for me. The vast majority of these emails are of the undeliverable type. What has just occurred to me is that some spammer could be putting my email address either in the sender box or the replyto box when the email is being sent. I have had a look at some of the full email headers and they appear to be genuine bounced emails, with an email address at my domain as the sender. Since I have a catch-all on my address, all emails to my domain come to me.
Can anyone tell me how to find this out for sure?
I know some people are going to suggest a better email provider with a spam filter, but that's another story and for the last few months I have lived with the serverside spam filter off.