Firewall Security

Firewall implementation can be hardware, software or combination of both. Today, it is mostly implemented for use on Internet access, restricting access on sites deemed inappropriate and to avoid Web attacks as well.

There are different types of firewall techniques, such as:

• Packet filter
  - inspecting each packet passing through the network, it checks against the user-defined rules in accepting or denying packets to go through.
  
  
• Application gateway
  - security methods apply to specific applications such as FTP and Telnet servers. 
  
  
• Circuit-level gateway
  - once a TCP or UCP connection is determined, security mechanisms are then applied. 
  
  
• Proxy server
  - efficiently hiding the true network address, it checks all messages coming to and from the network.