Firewall Network Securty

A firewall is a system or system group that runs the security access control between a secure internal network and an untrusted network such as internet.Firewall designed to permit the trusted data or data which is trusted by, refuse service vulnerabilities, preventing the internal network from outside attacks that could penetrate the firewall every time.  Generally also used to control access to anyone who has access to a private network from outside parties. Today, the term firewall is a common term that refers to systems that regulate communication between two different networks. Given the many companies currently have access to the 

Internet and also of course incorporated in it a network, the protection of digital capital of the company from attack by hackers (hackers, pemata-eye, or other data thieves) becomes mandatory.

 Firewall System Components
Firewalls can be either a PC, router, midrange, mainframe, UNIX workstation, or a combination of which is above.Firewall can consist of one or more functional components as follows:
  - Packet-filtering router
  - Application-level gateway (proxy)
  - Circuit-level gateway
Example Firewall Types
A firewall consists of one or more elements of software running on one or more hosts.
These types of firewalls are as follows:
  - Packet-filtering firewall
  - Dual-homed Gateway Firewall
  - Screened Host Firewall
  - Screened subnet firewall
Packet-filtering firewall
 • Consists of a router is placed between the external network and internal network safe.
 • Packet Filtering Rule is defined to allow or deny traffic.

Dual-homed Gateway Firewall
• Dual-homed host has at least two network interfaces and two IP addresses.
• IP forwarding is disabled on the firewall, resulting in IP traffic on both interfaces are messed up in the firewall because there is no other way for an IP through the firewall except through a proxy or SOCKS.
• Attacks that come from services that are not known to be blocked.

Screened host firewall
• Consists of a packet-filtering routers and application level gateway
• Host of application level gateway, known as the "bastion host"
• Consists of two packet filtering routers and a bastion host
Download Freen tutorial Cisco IOS Firewall

Posted in: Firewall