Saturday, April 19, 2008

SPAM - the continuing problem

One of the worst problems - perhaps the worst - on the internet these days is that of SPAM.

For those of you not (yet) afflicted with this 'disease', SPAM is vary simply emails that you didn't expect to receive and don't want. They may be trying to sell you a variety of performance enhancing drugs, a load of watches or simply trying to scare you into believing that your bank account is at risk.

For those badly afflicted, this may amount to over 1,000 unwanted emails EVERY DAY! So if you went on holiday for a couple of weeks, you might find 15,000 emails waiting for you, most of which you didn't want!

So that's the problem but what's the solution?

Well, the bad news is that there isn't an easy solution simply because you can't really define that a message IS spam! What may be spam for one person may not be for another. For example, you may receive what is probably a spam email and send it to me for analysis. When you send it to me it's no longer spam; it's now what I want to receive!

Even so there are still things which can be done to make the situation a bit more controllable.

I'm going to consider the problem in three parts; avoiding it arriving, getting rid of it before you download it and handling it once it gets to your computer.

Avoiding it Arriving

In order to see if we can avoid it arriving, it's useful to understand why it did arrive.

The fundamental problem is that your email address has been discovered by spam generators. This may be because your email address appears on a website or it may be because one of your 'friends' has sent out one of those, "send this to everyone in your mailbox" messages and by doing so has let everyone know your email address!

If your email address appears on a website, the web page can be recoded so that it is not so easy to extract it so if that's the case, contact Ken and he'll help you out - the methods for doing this are beyond the scope of this blog!

As for your friends letting all and sundry know what your email address is, short of changing your friends, there's probably not much that can be done about it, although a quiet word to your friend may help.

Even so, all may not be lost. Perhaps you have an email address something like ken@ourhouse.fsnet.co.uk. Many internet providers give you this form of 'infinite' email addresses where, in fact, anyname@ourhouse.fsnet.co.uk would get to you. Spam generators tend to generate email addresses based on the domain it's found (ourhouse.fsnet.co.uk) and may generate all sorts of addresses like ayxxi@..., 123ab@..., etc. so the first step is to limit your email system so that it simply doesn't allow anything other than the email address you actually want to use. In the case ig fsnet quoted in the example (later Wanadoo and now Orange) they provide some basic filtering capabilities so that you could set up a rule which says something like

If it's TO someone
who is NOT ken@ourhouse.fsnet.co.uk
then delete it

Getting rid of it before you download it

OK, so despite your best efforts, it's still got to your mail box, so what now?

There are two ways of tackling this problem; one is to pay someone else to help (i.e. use an external spam filter like www.spamdefy.com) and one is to control it from your email client. These can be thought of the easy way and the hard way!

Using the easy way, you sign up for an external spam filter system and that feeds your emails through its own processing, identifying emails which contain viruses, emails which come from known bad senders and those which look as though they are 'baddies'. Even so, you still have to sign on to its website to monitor your emails to make sure that nothing which you wanted has been blocked, and to let it know what are 'bad' emails.

The second (hard) approach is to set up filters in your email client and the details of this are beyond the scope of this blog. What basically will happen is that you'll set your email client to download just the headers of the messages (i.e. the bits which say what the subject is, who it's to and who it's from) and then define various rules to decide whether you will delete the original message or download it fully because it looks OK. This approach is not for the fainthearted!

Handling it once it gets to your computer

So despite your best efforts, you've still got spam arriving, so what now?

In this case I'd suggest a (free) spam filtering piece of software be installed, and one such product is Spamihilator (www.spamihilator.com). This is fairly simple to understand and works on the idea that emails downloaded go through it and you train it to understand what you think are spam emails and what are OK. Eventually it gets pretty good at making the right decisions and the email that arrives in your inbox is mostly what you want. Again, you do have to check it regularly to make sure that nothing has been blocked that you wanted!

As ever, if you have any problems or questions about this topic or you need help setting up an effective spam blocking system, just Call on Ken!