Symptoms

"Mail delivery failed"
"Returned mail: user unknown"
"Returned due to virus..."
"It seems that you have sent an attachment. This account does not accept attachments."

There may be a few reasons why you may be getting this.

1. You have a virus on your computer that is sending out email with your account.

2. Spammers are forging the "From:" field with your email address, so when the email reaches an unkown recipient, it gets returned to you.

3. Somebody that you know may have a computer that has been infected with a virus. The virus tries to spread itself by sending itself to other people by forging the "From:" address using an email address that's in the infected system's address book (which may be your email address).

1. Make sure your anti-virus software is up-to-date by downloading any updates.

2. Run a complete scan on your computer to see if this finds any viruses. You may still get returned emails until all mail servers on the internet have returned these emails. Visit out FAQ on spam to learn more: http://www.humboldt1.com/tutorials/spam/index.html

Unfotunately, it is very difficult to prevent a bounced email from coming into your inbox because the bounced email is a legitmate notice that the intended recipient does not exist. We recommend to simply delete those emails.

Solution to reason 3)

You may want to contact everyone who has your email address in their computer's address book and suggest that they might want to check their systems for viruses. However, this may not be the problem.

How did they get my email address?

Spammers have many techniques that they use to harvest email address with range from buying a list of email addresses from other spammers to executing "dictionary" attacks where they send an email to a@humboldt1.com, aardvark@humboldt1.com, adam@humboldt1.com, andrew@humboldt1.com, ...etc. Discussion of the different techniques are outside the scope of this document, but more information can be found using a search engine like Google,