How do I stop someone from sending me harassing email?

First, let me be clear: you cannot use technology to stop someone from emailing you if they know your email address. The only technological solutions you have available to you relate to what you do with the email once it arrives.

Now, you'll note I said "technological solutions". If the emails truly meet the legal definition of harassment, then you should proceed immediately to your local law enforcement officials and legal system. If the harassment is illegal or threatening you may be able to have action taken. I'm in no way a lawyer, but if it's reached that level of concern then you should absolutely seek out legal advice.

My realm is technology, so let's look at that.

•

Your goal is simple: even though he may continue to send it, you never want to see the email from this particular individual.

Much of what you can do depends greatly on your email provider, and the specific email program that you're using.

Many email providers allow you to specify "black lists" or "block lists" - email addresses from whom you never want to receive email. Windows Live Hotmail, for example, provides a Blocked Senders facility which allows you to "Manage who is blocked from sending you e-mail. Messages from blocked senders are automatically deleted." You can access this off the Options menu within Windows Live Hotmail. Other mail services, both web-based and downloadable, may have a similar facility - you'll need to check with whomever it is you're using for your email.

If your email provider does not include such a facility, you might look into your email program and see if it supports what are often called "filters" or "rules". Programs like Thunderbird, Outlook, Outlook Express and others, and even some of the web based email services such as GMail, allow you to define rules that are applied to messages as they arrive, and they all at least support the basic rule: "if the message is from this address, delete it immediately".

Both of these approaches, blacklists and rules, sound almost perfect, right? Except there's one problem, and you're already experiencing it.

What if the sender changes the email address he's sending from?

Then things get much more difficult.

And, to be honest, with most services you're pretty much out of options at this point. You can start classifying the offending email as Junk or Spam, in the hopes that the spam filters will "learn" what you consider spam and eventually start junking it for you automatically, but it's not at all clear how effective that technique will be. It depends very heavily on the characteristics of the spam filters used by the email service you use.

Some email programs will allow you to set up advanced rules based on many other characteristics of incoming mail. For example, if your sender uses a particular phrase or signs the email a particular way every time, you can instruct your email program "if the email contains the phrase 'banned phrase' then delete it". Similarly, if your recipient is sending from an unchanging IP address, and if that IP address is visible in the email headers, then you could do the same "if it's from this IP address, delete it". (Be careful here; IP addresses can change, and you need to be positive you're banning the sender's IP, not the services IP or you could be blocking anyone who uses the same service.)

Unfortunately most web-based email services do not provide this advanced level of functionality.

Finally, you can complain to this person's ISP. Typically harassment is consider a violation of most ISP's terms of service. The problem here is that the ISP might not have the time or inclination to deal with these types of complaints, and it's unclear how much justification they might need. But it's worth a shot.

The bottom line is that it's extremely difficult to thwart someone who's truly motivated to send you email. As you can see there are many ways around the various roadblocks you can set up. If none of the above works, short of legal action my recommendation is the ultimate control you have: the delete key.