SPI Firewalls: How It Works

Firewall got it’s own importance in any computer networks,As it secure you by inspecting all the data packets in and out from your own home/office network.If the rules created on the firewall is proper,it will prevent  unauthorized access to any enterprise’s network.SPI firewalls or stateful packet inspection firewalls do this job properly by examining the packet header and  destination port for authentication, also SPI firewalls will check the entire packet’s content before determining whether to allow it passage into the network.

Why SPI Firewalls ? 

All the SPI firewalls can be coming with an  access control list, a database of trusted entities and their network access privileges. Stateful packet inspection firewalls or SPI firewalls can be configured to drop any packets sent from the sources that not listed within the access control list, This will prevent the denial-of-service attack, in which an attacker floods the network with incoming traffic in an effort to bring down its resources and render it unable to respond to legitimate requests.As this type of attack is mostly attempted by the hackers.

SPI firewalls will be able to examine the IP packet characteristics of those used in known hacking exploits such as ip spoofing,DoS attacks and SPI firewalls can drop any packet that identified as potentially dangerous.


In normal router case,The Routers NAT translation will block random outside attacks from knowing your computer IP address but with SIP firewall equipped router,it will looks at the known packets and discards the packets that it think bad.As you know,your windows firewall is not enough to block any suspicious packets as it is designed to protect your computer from unsolicited incoming data but it will not take care the data your PC sending out.if you got hacked or fooled into installing a trojan or virus on your computer. A router would let the data out and the windows firewall not able to control the outgoing data.Here comes the third party software firewalls in rescue.

The new generation broadband routers from different manufactures got the ability to configure it as an SPI firewall but it should be done by someone who have good knowledge in network configuration.

In many cases lot of third party security softwares these days coming with SIP firewalls option for both outbound and inbound protection.Check them out in the market today and secure your home network.

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