FIREWALLS

Firewalls are specialized computers with multiple network interface ports that are designed to control network access to an organization's network resources. Firewalls may be used between an organization and the Internet or within an organization itself. A firewall will have at least one 'inside' and one 'outside' zones, each served by a network interface. Inside and outside are defined by whether the interface serves the protected network (inside) or the unprotected network (outside). Traffic flow in either direction is filtered in order to control access to the network and outside resources.

Firewalls monitor all traffic, blocking network activity that does not conform to security policies set by the security administrator.

Normally, your data is passed down through your TCP/IP stack and transmitted to a far end station. Firewalls intercept all traffic flowing betweeen the network and data link layers, to guarantee no traffic that is not permitted makes it past that network interface.

• Firewall Types
  • Hardware
    • Network Appliance
  • Software
    • Network Appliance
    • Host Application
• Firewall Characteristics
  • STATEFUL vs. STATELESS
  • RULES BASED vs. POLICY BASED
  • PACKET INSPECTION vs. PACKET FILTERING
  • STATEFUL PACKET INSPECTION
  • PROXIES
  • Network Address Translation (NAT/NAT with Overload)
  • Virtual Private Networking (VPN)

 

 

 

---