A security measure used to protect computers on a local networks from outside accesses . This archieved by making a single gateway between the network and the outside world through which all the packets have to travel. Thiss gateway is then configured to allow only certain types of accesses. For example, it is possible to configure a firewall to allow only outside access on ports 21 (FTP) and 23(telnet) and refuse all other connection. It also possible to forbit accesses from certain outside IP addresses, however, this really isn't that secure since it is always posible to possible to spoof your IP.
Tags: Firewall, Virus scanning, Clean virus, Avast, Virus cleaner, Virus