If you’re not an I.T. wiz, some of the descriptions of the router security features might seem more like a foreign language than anything aimed at helping you decipher which integrated services router is right for your company. We’re here to help you understand the security features of a router by breaking them down for you one at a time. Let’s talk about Firewalls.

First off, what is a Firewall?

A firewall is a device that provides basic security for your computer or network. Network-level firewalls are typically built into your router and acts as sort of a gatekeeper for all the packets of data that enter your network from the expansive internet (which can be a dangerous place). The firewall examines each data packet and looks at the data packet’s header. The header must match a list of ‘rules’ that the firewall knows, and if it does, it can pass. If it doesn’t, the firewall stops it. Who sets these rules? The network administrator typically sets the rules for the firewall to follow, but can also set up the opposite—a set of rules that are negative. If the firewall detects that a packet’s header contains something on the firewall’s list of ‘negative rules,’ it will also stop the packet in its tracks.

While in theory, a firewall might be enough of a security system to protect a network, it usually isn’t. Most firewalls do not detect and defuse viruses, worms, and most application-specific attacks. To the firewall, the headers for these ‘bad packets’ appear to be good headers which is why additional security like and IDS, IPS, application-level firewalls, and anti-spyware/anti-virus applications are needed for more reliable network protection.

Think of it like this. Your network is a night club. The firewall is the bouncer who stands at the door letting people come in. Even the biggest, most intimidating bouncer has no way of knowing that the underage boy showing him a fake ID is really underage. To the bouncer who sees the fake ID, the kid looks legit. And so he lets the kid go in, and in turn, the boy is caught drinking and the entire club is shut down—which is exactly what malware like a virus or worm can do to your network. An IDS/IPS combo, and anti-spyware/anti-virus applications along with application-level firewalls take a harder look at the underage kid’s I.D. So once the kid gets past the bouncer, he hands his ID to a hostess who runs it through a scanner. The ID comes up as a fake, the threat is detected, and the kid is then promptly kicked out of the club before ever reaching the bar. These added layers of security are like the ID scanner. They use complex rules when they examine a packet, scrutinizing its content, its source, the ports involved, the destination address, the type of traffic it is, and the applications being called to open it. Only under this advanced scrutiny can hidden attackers like viruses and worms be detected.