1 AQA ICT AS Level © Nelson Thornes Firewalls and Virus Checkers
2 AQA ICT AS Level © Nelson Thornes Firewalls What does a firewall do? It checks the data coming into a computer system via the Internet against a set of rules or criteria, and only lets permitted material through. It also helps to prevent unauthorised access to computer networks.
3 AQA ICT AS Level © Nelson Thornes They work by: Allowing all traffic unless it does not meet certain criteria. Allowing no traffic unless it meets certain criteria. Basic criteria could be: nature of the data source of the data Firewalls
4 AQA ICT AS Level © Nelson Thornes Firewalls can be hardware or software Firewalls Hardware Software
5 AQA ICT AS Level © Nelson Thornes Firewalls Firewall software is usually included as part of the operating system. Specialist firewall software can also be purchased, for example:
6 AQA ICT AS Level © Nelson Thornes How can organisations prevent unauthorised access? A firewall can log all attempts to enter a private network. Multiple attempts may suggest unauthorised attempts. This warning would allow extra security to be put in place. An audit trail is a record that shows who has accessed an ICT system and what they have done. Avoid using the term hacking in an exam, as this is rather vague. Unauthorised access
7 AQA ICT AS Level © Nelson Thornes Firewalls How does the firewall in your own institution work? How does your institution prevent access to unsuitable websites? How does your institution prevent unauthorised access?
8 AQA ICT AS Level © Nelson Thornes Anti-virus software continually scans for viruses, including Trojans and Worms. It must be kept up-to-date, though, as new viruses appear all the time. Companies usually charge a subscription for updates. Virus Checkers
9 AQA ICT AS Level © Nelson Thornes Anti-virus software maintains a database of known viruses. Incoming data files, through , downloads or removable media, are checked against the database. Suspicious files are deleted or put into a safe quarantined area for further investigation. Scheduled scans of all data files on the system can be done automatically. Virus definitions need to be kept up-to-date and software subscriptions include regular downloads of updates. Anti-virus software