A firewall is a program or hardware device that filters information coming from the Internet connection to your LAN or computer. If an incoming packet of information is flagged by the filters, it is not allowed through. Without some sort of a firewall, computers are directly accessible to anyone on the Internet. A person who knows what he or she is doing can probe those computers, try to make FTP connections to them, try to make telnet connections to them and so on. If there is a security hole, hackers can get in and exploit the security hole.

With a firewall in place, the story is much different. With a firewall at every connection to the Internet you implement security rules. For example, one of the security rules inside the company might be:

Out of the 25 computers inside a particular company, only one of them is permitted to receive public FTP traffic. Allow FTP connections only to that one computer and prevent them on all others. A company can set up rules like this for FTP servers, Web servers, Telnet servers and so on. In addition, the company can control how employees connect to Web sites, whether files are allowed to leave the company over the network and so on. A firewall gives a company tremendous control over how people use the network. Firewalls use one or more of three methods to control traffic flowing in and out of the network:

Packet filtering - Packets are analyzed against a set of filters. Packets that make it through the filters are sent to the requesting system and all others are discarded.
Proxy service - Information from the Internet is retrieved by the firewall and then sent to the requesting system and vice versa.
Stateful inspection - A newer method that doesn't examine the contents of each packet but instead compares certain key parts of the packet to a database of trusted information. Information traveling from inside the firewall to the outside is monitored for specific defining characteristics, then incoming information is compared to these characteristics. If the comparison yields a reasonable match, the information is allowed through. Otherwise it is discarded.

We sell and service a full line of Firewall products from SONICWALL.

Call us for a free consultation and/or pricing 1-800-506-3082.

We service the Phoenix Metro area including: Tempe, Mesa, Scottsdale, Fountain Hills, Glendale, Gilbert, Chandler, Cave Creek, Deer Valley, Peoria, Goodyear, Avondale, Sun City, Sun City West, Surprise, El Mirage, Tolleson, Casa Grande, Prescott, Payson, Pine, Strawberry, Wickenburg, Globe, Show Low, Eloy, Gila Bend, Tucson, Arizona.