How can I stay secure using broadband?

Your broadband provider assigns your router a unique numeric identifier - an IP address - that is published on the internet so any other computer on the net can connect to yours. This is probably not the ideal position to be in, but you can take control using a hardware firewall.

You can tell the firewall which computers are allowed to connect with yours and whether they can connect of their own free will or need an invitation first.

So you might choose to prevent any connections to your computer that you have not initiated - the safest normal option - or maybe allow uninvited connections to a specific computer you use to run a shopping cart or for receiving internet phone calls. You might need specialist help to set up a hardware firewall.

To manage the programs you use for services such as email, web access and instant messaging - which is where most of the security risk resides for a typical user - anti-virus, anti-spyware and software firewalls come into their own.

Anti-virus and anti-spyware tools both detect ‘malware’ - programs that might be malicious. If you keep them running in the background they will detect malware hidden in email attachments and files you download from the web as soon as you try to open them.

Some tools couple themselves to your web browser so they can also detect malware a bit earlier - when it is downloaded.

But no anti-virus or anti-spyware tool can detect all the threats. A small percentage of the latest malware - ‘leading edge’ malware - can slip through, although if you're using the web fairly responsibly this is less likely to occur.

A software firewall can help prevent some of what might slip through your anti-malware tools doing too much damage. Like its hardware partner, it controls communication between devices - but in this case, also between programs and the internet. It can prevent malware that does sneak in updating itself or sending out your private information. It can also make your computer invisible to the internet by 'stealthing' it so it's less easy for attackers to find.

Even if you have a firewall and anti-malware tools, you can still be unsecure if you download suspect files indiscriminately. A very common attack is to send a spam email advertising a tempting video clip, maybe a current pop video. When you try to view it, you are prompted to download a 'codec' - supposedly a file needed to view the video. But this is not what it seems. It's a malicious program that installs itself on your computer.

This is cunning applied psychology. It offers you something you want, frustrates you in getting it and then provides a 'solution' to invite you into the trap. Most people will fall for this if they're interested in the offer and not aware of the scam. And it is likely to be leading edge malware that your tools may not detect. So, if you ever get a prompt like this, ignore it - say 'no'. Nine times out of 10 it will be legitimate, but you just can’t be sure.

You should also consider your privacy. For example, emails are sent across the internet by bouncing them from one computer to the next in a chain of so called 'hops' that can be quite long - London to Watford via Texas is not unknown.

At each hop, the email is stored temporarily on a computer before being forwarded to the next. It's possible, if unusual, that any of these computers might save a copy of the email to be read by a complete stranger. So maybe you should encrypt messages you really want to keep private. Similarly, you should actively check that your connection is encrypted on shopping and banking sites. For peace of mind just remain vigilant.