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Firewalls and Virus Checkers

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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.

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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

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Firewalls can be hardware or software

Firewalls

Hardware

Software

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FirewallsFirewall software is usually included as part of the operating system.

Specialist firewall software can also be purchased, for example:

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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

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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?

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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

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•Anti-virus software maintains a database of known viruses.•Incoming data files, through e-mail, 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