Why do I keep getting these emails from non-existent email addresses on my domain?

Question

My wife's got a website/domain for the business she owns, and lately she's been getting emails from email addresses on her domain that don't exist. So, she has like maybe five valid email addresses (i.e., hername@herdomainname.com, and a few for employees) and she's seeing email come in addressed to things like curtis35398@herdomainname.com and other clearly generated addresses.

Even more troubling is when she gets the Mail delivery failed: returning message to sender messages about an email claiming to have attempted to be sent from these made up email addresses, so either someone's using her domain name to try and send email, or these emails are just designed to look that way.

Her email is currently hosted by Gmail/Google Apps and the domain name is through GoDaddy (along with the website hosting).

Does anyone have any idea what's going on here, what we can do to fix/stop it, and what if anything might have caused it? We both run NOD32 and she runs Chrome as her main web browser so I don't think that it's a virus or something (more likely someone just being a jerk) but I can't rule it out entirely.

Answer 1

It's a common problem, the email addresses are forged (this is easy to do with Internet email) usually the senders of spam choose random "from" addresses constructed from their list of target addresses. The flood should subside after a few days (or weeks).

There is nothing really practical you can do to stop the spammers using your domain name in their forged "from" address.

There were some initiatives (e.g. SPF) to use special DNS records that email recipients could use to verify the sending server was authorised to send mail "from" a specific domain, but these methods are not universally adopted.