What is SPI?
SPI stands for “Stateful Packet Inspection” and is a smart Firewall that can examine each packet of data, inbound and outbound, and automatically detect and block common forms of attack by hackers. Other benefits are that because of the extra attention to detail that an SPI Firewall provides, rules and filters can be far more comprehensive. With just a NAT Firewall, a rule can be created to allow access by other Internet users to a particular PC on your Network through a particular port. With an SPI firewall the same rule can include limitations based on the source of the user, the time of day and which days of the week you want access to occur, and can also include similar rules for outbound activity. For example, this would allow a rule to be created that will prevent users on your Network from accessing FTP servers or even websites during certain periods of the day.
