Security - Firewall

 

 

A firewall is simply a program or hardware device that filters the information coming or outgoing through the Internet connection.

 

Firewall use one or more methods to control traffic flowing in and out of the network:

 

Packet Filtering

Packets (small chunks of data) 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.

 

Control + Analyze + Prevent